[Android] Use UIResource for overscroll glow

Introduce a SystemUIResourceManager class for loading and providing access to
shared UIResourceId's.  Wire this class to the existing OverscrollGlow effect,
using the shared id's with a UIResourceLayer for both glow and edge layers.

This patch is a subset of powei@'s original SystemUIResource patch found at
https://codereview.chromium.org/377013002/.

BUG=326326

Review URL: https://codereview.chromium.org/422013003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288095 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/android/edge_effect.cc

@@ -5,6 +5,8 @@
 #include "content/browser/android/edge_effect.h"
 
 #include "cc/layers/layer.h"
+#include "cc/layers/ui_resource_layer.h"
+#include "ui/base/android/system_ui_resource_manager.h"
 
 namespace content {
 
@@ -118,52 +120,70 @@ gfx::Size ComputeBounds(EdgeEffect::Edge edge,
   };
 }
 
-void DisableLayer(cc::Layer* layer) {
-  DCHECK(layer);
-  layer->SetIsDrawable(false);
-  layer->SetTransform(gfx::Transform());
-  layer->SetOpacity(1.f);
-}
+}  // namespace
+
+class EdgeEffect::EffectLayer {
+ public:
+  EffectLayer(ui::SystemUIResourceManager::ResourceType resource_type,
+              ui::SystemUIResourceManager* resource_manager)
+      : ui_resource_layer_(cc::UIResourceLayer::Create()),
+        resource_type_(resource_type),
+        resource_manager_(resource_manager) {}
+
+  ~EffectLayer() { ui_resource_layer_->RemoveFromParent(); }
+
+  void SetParent(cc::Layer* parent) {
+    if (ui_resource_layer_->parent() != parent)
+      parent->AddChild(ui_resource_layer_);
+    ui_resource_layer_->SetUIResourceId(
+        resource_manager_->GetUIResourceId(resource_type_));
+  }
 
-void UpdateLayer(cc::Layer* layer,
-                 EdgeEffect::Edge edge,
+  void Disable() { ui_resource_layer_->SetIsDrawable(false); }
+
+  void Update(EdgeEffect::Edge edge,
               const gfx::SizeF& window_size,
               int offset,
               int height,
               float opacity) {
-  DCHECK(layer);
-  layer->SetIsDrawable(true);
+    ui_resource_layer_->SetUIResourceId(
+        resource_manager_->GetUIResourceId(resource_type_));
+    ui_resource_layer_->SetIsDrawable(true);
     gfx::Size bounds = ComputeBounds(edge, window_size, height);
-  layer->SetTransformOrigin(
+    ui_resource_layer_->SetTransformOrigin(
         gfx::Point3F(bounds.width() * 0.5f, bounds.height() * 0.5f, 0));
-  layer->SetTransform(ComputeTransform(edge, window_size, offset, height));
-  layer->SetBounds(bounds);
-  layer->SetOpacity(Clamp(opacity, 0.f, 1.f));
-}
+    ui_resource_layer_->SetTransform(
+        ComputeTransform(edge, window_size, offset, height));
+    ui_resource_layer_->SetBounds(bounds);
+    ui_resource_layer_->SetOpacity(Clamp(opacity, 0.f, 1.f));
+  }
 
-} // namespace
+  scoped_refptr<cc::UIResourceLayer> ui_resource_layer_;
+  ui::SystemUIResourceManager::ResourceType resource_type_;
+  ui::SystemUIResourceManager* resource_manager_;
+
+  DISALLOW_COPY_AND_ASSIGN(EffectLayer);
+};
 
-EdgeEffect::EdgeEffect(scoped_refptr<cc::Layer> edge,
-                       scoped_refptr<cc::Layer> glow)
-  : edge_(edge)
-  , glow_(glow)
-  , edge_alpha_(0)
-  , edge_scale_y_(0)
-  , glow_alpha_(0)
-  , glow_scale_y_(0)
-  , edge_alpha_start_(0)
-  , edge_alpha_finish_(0)
-  , edge_scale_y_start_(0)
-  , edge_scale_y_finish_(0)
-  , glow_alpha_start_(0)
-  , glow_alpha_finish_(0)
-  , glow_scale_y_start_(0)
-  , glow_scale_y_finish_(0)
-  , state_(STATE_IDLE)
-  , pull_distance_(0) {
-  // Prevent the provided layers from drawing until the effect is activated.
-  DisableLayer(edge_.get());
-  DisableLayer(glow_.get());
+EdgeEffect::EdgeEffect(ui::SystemUIResourceManager* resource_manager)
+    : edge_(new EffectLayer(ui::SystemUIResourceManager::OVERSCROLL_EDGE,
+                            resource_manager)),
+      glow_(new EffectLayer(ui::SystemUIResourceManager::OVERSCROLL_GLOW,
+                            resource_manager)),
+      edge_alpha_(0),
+      edge_scale_y_(0),
+      glow_alpha_(0),
+      glow_scale_y_(0),
+      edge_alpha_start_(0),
+      edge_alpha_finish_(0),
+      edge_scale_y_start_(0),
+      edge_scale_y_finish_(0),
+      glow_alpha_start_(0),
+      glow_alpha_finish_(0),
+      glow_scale_y_start_(0),
+      glow_scale_y_finish_(0),
+      state_(STATE_IDLE),
+      pull_distance_(0) {
 }
 
 EdgeEffect::~EdgeEffect() { }
@@ -173,8 +193,8 @@ bool EdgeEffect::IsFinished() const {
 }
 
 void EdgeEffect::Finish() {
-  DisableLayer(edge_.get());
-  DisableLayer(glow_.get());
+  edge_->Disable();
+  glow_->Disable();
   pull_distance_ = 0;
   state_ = STATE_IDLE;
 }
@@ -359,8 +379,8 @@ void EdgeEffect::ApplyToLayers(gfx::SizeF window_size,
   // An empty window size, while meaningless, is also relatively harmless, and
   // will simply prevent any drawing of the layers.
   if (window_size.IsEmpty()) {
-    DisableLayer(edge_.get());
-    DisableLayer(glow_.get());
+    edge_->Disable();
+    glow_->Disable();
     return;
   }
 
@@ -368,13 +388,26 @@ void EdgeEffect::ApplyToLayers(gfx::SizeF window_size,
   const int scaled_glow_height = static_cast<int>(
       std::min(glow_height * glow_scale_y_ * kGlowHeightToWidthRatio * 0.6f,
                glow_height * kMaxGlowHeight) + 0.5f);
-  UpdateLayer(
-      glow_.get(), edge, window_size, offset, scaled_glow_height, glow_alpha_);
+  glow_->Update(edge, window_size, offset, scaled_glow_height, glow_alpha_);
 
   // Edge
   const int scaled_edge_height = static_cast<int>(edge_height * edge_scale_y_);
-  UpdateLayer(
-      edge_.get(), edge, window_size, offset, scaled_edge_height, edge_alpha_);
+  edge_->Update(edge, window_size, offset, scaled_edge_height, edge_alpha_);
+}
+
+void EdgeEffect::SetParent(cc::Layer* parent) {
+  edge_->SetParent(parent);
+  glow_->SetParent(parent);
+}
+
+// static
+void EdgeEffect::PreloadResources(
+    ui::SystemUIResourceManager* resource_manager) {
+  DCHECK(resource_manager);
+  resource_manager->PreloadResource(
+      ui::SystemUIResourceManager::OVERSCROLL_EDGE);
+  resource_manager->PreloadResource(
+      ui::SystemUIResourceManager::OVERSCROLL_GLOW);
 }
 
 } // namespace content

content/browser/android/edge_effect.h

@@ -6,7 +6,7 @@
 #define CONTENT_BROWSER_ANDROID_EDGE_EFFECT_H_
 
 #include "base/basictypes.h"
-#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
 #include "ui/gfx/size_f.h"
 
@@ -14,6 +14,10 @@ namespace cc {
 class Layer;
 }
 
+namespace ui {
+class SystemUIResourceManager;
+}
+
 namespace content {
 
 /* |EdgeEffect| mirrors its Android counterpart, EdgeEffect.java.
@@ -24,7 +28,7 @@ namespace content {
  * All coordinates and dimensions are in device pixels.
  */
 class EdgeEffect {
-public:
+ public:
   enum Edge {
     EDGE_TOP = 0,
     EDGE_LEFT,
@@ -33,7 +37,7 @@ public:
     EDGE_COUNT
   };
 
-  EdgeEffect(scoped_refptr<cc::Layer> edge, scoped_refptr<cc::Layer> glow);
+  explicit EdgeEffect(ui::SystemUIResourceManager* resource_manager);
   ~EdgeEffect();
 
   void Pull(base::TimeTicks current_time, float delta_distance);
@@ -50,8 +54,11 @@ public:
                      float glow_height,
                      float offset);
 
-private:
+  void SetParent(cc::Layer* parent);
+
+  static void PreloadResources(ui::SystemUIResourceManager* resource_manager);
 
+ private:
   enum State {
     STATE_IDLE = 0,
     STATE_PULL,
@@ -60,8 +67,9 @@ private:
     STATE_PULL_DECAY
   };
 
-  scoped_refptr<cc::Layer> edge_;
-  scoped_refptr<cc::Layer> glow_;
+  class EffectLayer;
+  scoped_ptr<EffectLayer> edge_;
+  scoped_ptr<EffectLayer> glow_;
 
   float edge_alpha_;
   float edge_scale_y_;

content/browser/android/overscroll_glow.cc

@@ -6,11 +6,8 @@
 
 #include "base/debug/trace_event.h"
 #include "base/lazy_instance.h"
-#include "base/threading/worker_pool.h"
-#include "cc/layers/image_layer.h"
+#include "cc/layers/layer.h"
 #include "content/browser/android/edge_effect.h"
-#include "skia/ext/image_operations.h"
-#include "ui/gfx/android/java_bitmap.h"
 
 using std::max;
 using std::min;
@@ -20,57 +17,9 @@ namespace content {
 namespace {
 
 const float kEpsilon = 1e-3f;
-const int kScaledEdgeHeight = 12;
-const int kScaledGlowHeight = 64;
 const float kEdgeHeightAtMdpi = 12.f;
 const float kGlowHeightAtMdpi = 128.f;
 
-SkBitmap CreateSkBitmapFromAndroidResource(const char* name, gfx::Size size) {
-  base::android::ScopedJavaLocalRef<jobject> jobj =
-      gfx::CreateJavaBitmapFromAndroidResource(name, size);
-  if (jobj.is_null())
-    return SkBitmap();
-
-  SkBitmap bitmap = CreateSkBitmapFromJavaBitmap(gfx::JavaBitmap(jobj.obj()));
-  if (bitmap.isNull())
-    return bitmap;
-
-  return skia::ImageOperations::Resize(
-      bitmap, skia::ImageOperations::RESIZE_BOX, size.width(), size.height());
-}
-
-class OverscrollResources {
- public:
-  OverscrollResources() {
-    TRACE_EVENT0("browser", "OverscrollResources::Create");
-    edge_bitmap_ =
-        CreateSkBitmapFromAndroidResource("android:drawable/overscroll_edge",
-                                          gfx::Size(128, kScaledEdgeHeight));
-    glow_bitmap_ =
-        CreateSkBitmapFromAndroidResource("android:drawable/overscroll_glow",
-                                          gfx::Size(128, kScaledGlowHeight));
-  }
-
-  const SkBitmap& edge_bitmap() const { return edge_bitmap_; }
-  const SkBitmap& glow_bitmap() const { return glow_bitmap_; }
-
- private:
-  SkBitmap edge_bitmap_;
-  SkBitmap glow_bitmap_;
-
-  DISALLOW_COPY_AND_ASSIGN(OverscrollResources);
-};
-
-// Leaky to allow access from a worker thread.
-base::LazyInstance<OverscrollResources>::Leaky g_overscroll_resources =
-    LAZY_INSTANCE_INITIALIZER;
-
-scoped_refptr<cc::Layer> CreateImageLayer(const SkBitmap& bitmap) {
-  scoped_refptr<cc::ImageLayer> layer = cc::ImageLayer::Create();
-  layer->SetBitmap(bitmap);
-  return layer;
-}
-
 bool IsApproxZero(float value) {
   return std::abs(value) < kEpsilon;
 }
@@ -83,25 +32,18 @@ gfx::Vector2dF ZeroSmallComponents(gfx::Vector2dF vector) {
   return vector;
 }
 
-// Force loading of any necessary resources.  This function is thread-safe.
-void EnsureResources() {
-  g_overscroll_resources.Get();
-}
-
 }  // namespace
 
-scoped_ptr<OverscrollGlow> OverscrollGlow::Create(bool enabled) {
-  // Don't block the main thread with effect resource loading during creation.
-  // Effect instantiation is deferred until the effect overscrolls, in which
-  // case the main thread may block until the resource has loaded.
-  if (enabled && g_overscroll_resources == NULL)
-    base::WorkerPool::PostTask(FROM_HERE, base::Bind(EnsureResources), true);
-
-  return make_scoped_ptr(new OverscrollGlow(enabled));
+scoped_ptr<OverscrollGlow> OverscrollGlow::Create(
+    ui::SystemUIResourceManager* resource_manager) {
+  return make_scoped_ptr(new OverscrollGlow(resource_manager));
 }
 
-OverscrollGlow::OverscrollGlow(bool enabled)
-    : enabled_(enabled), initialized_(false) {}
+OverscrollGlow::OverscrollGlow(ui::SystemUIResourceManager* resource_manager)
+    : enabled_(true), initialized_(false), resource_manager_(resource_manager) {
+  DCHECK(resource_manager_);
+  EdgeEffect::PreloadResources(resource_manager_);
+}
 
 OverscrollGlow::~OverscrollGlow() {
   Detach();
@@ -222,6 +164,9 @@ void OverscrollGlow::UpdateLayerAttachment(cc::Layer* parent) {
 
   if (root_layer_->parent() != parent)
     parent->AddChild(root_layer_);
+
+  for (size_t i = 0; i < EdgeEffect::EDGE_COUNT; ++i)
+    edge_effects_[i]->SetParent(root_layer_);
 }
 
 void OverscrollGlow::Detach() {
@@ -234,22 +179,10 @@ bool OverscrollGlow::InitializeIfNecessary() {
   if (initialized_)
     return true;
 
-  const SkBitmap& edge = g_overscroll_resources.Get().edge_bitmap();
-  const SkBitmap& glow = g_overscroll_resources.Get().glow_bitmap();
-  if (edge.isNull() || glow.isNull()) {
-    Disable();
-    return false;
-  }
-
   DCHECK(!root_layer_);
   root_layer_ = cc::Layer::Create();
-  for (size_t i = 0; i < EdgeEffect::EDGE_COUNT; ++i) {
-    scoped_refptr<cc::Layer> edge_layer = CreateImageLayer(edge);
-    scoped_refptr<cc::Layer> glow_layer = CreateImageLayer(glow);
-    root_layer_->AddChild(edge_layer);
-    root_layer_->AddChild(glow_layer);
-    edge_effects_[i] = make_scoped_ptr(new EdgeEffect(edge_layer, glow_layer));
-  }
+  for (size_t i = 0; i < EdgeEffect::EDGE_COUNT; ++i)
+    edge_effects_[i] = make_scoped_ptr(new EdgeEffect(resource_manager_));
 
   initialized_ = true;
   return true;

content/browser/android/overscroll_glow.h

@@ -14,8 +14,8 @@
 
 class SkBitmap;
 
-namespace cc {
-class Layer;
+namespace ui {
+class SystemUIResourceManager;
 }
 
 namespace content {
@@ -26,11 +26,11 @@ namespace content {
  */
 class OverscrollGlow {
  public:
-  // Create a new effect. If |enabled| is false, the effect will remain
-  // deactivated until explicitly enabled.
-  // Note: No resources will be allocated until the effect is both
-  //       enabled and an overscroll event has occurred.
-  static scoped_ptr<OverscrollGlow> Create(bool enabled);
+  // Create a new effect. |resource_manager| provides the resource for the
+  // effect. |resource_manager| must outlive the effect.  The effect is
+  // activated by default.
+  static scoped_ptr<OverscrollGlow> Create(
+      ui::SystemUIResourceManager* resource_manager);
 
   ~OverscrollGlow();
 
@@ -70,7 +70,7 @@ class OverscrollGlow {
  private:
   enum Axis { AXIS_X, AXIS_Y };
 
-  OverscrollGlow(bool enabled);
+  explicit OverscrollGlow(ui::SystemUIResourceManager* resource_manager);
 
   // Returns whether the effect is initialized.
   bool InitializeIfNecessary();
@@ -94,6 +94,7 @@ class OverscrollGlow {
   bool initialized_;
 
   scoped_refptr<cc::Layer> root_layer_;
+  ui::SystemUIResourceManager* resource_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(OverscrollGlow);
 };

content/browser/android/system_ui_resource_manager_impl.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/android/system_ui_resource_manager_impl.h"
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/location.h"
+#include "base/observer_list.h"
+#include "base/threading/worker_pool.h"
+#include "cc/resources/ui_resource_bitmap.h"
+#include "content/public/browser/android/ui_resource_client_android.h"
+#include "content/public/browser/android/ui_resource_provider.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "ui/gfx/android/java_bitmap.h"
+
+namespace content {
+
+class SystemUIResourceManagerImpl::Entry
+    : public content::UIResourceClientAndroid {
+ public:
+  explicit Entry(UIResourceProvider* provider) : id_(0), provider_(provider) {
+    DCHECK(provider);
+  }
+
+  virtual ~Entry() {
+    if (id_)
+      provider_->DeleteUIResource(id_);
+    id_ = 0;
+  }
+
+  void SetBitmap(const SkBitmap& bitmap) {
+    DCHECK(bitmap_.empty());
+    DCHECK(!bitmap.empty());
+    DCHECK(!id_);
+    bitmap_ = bitmap;
+  }
+
+  cc::UIResourceId GetUIResourceId() {
+    if (bitmap_.empty())
+      return 0;
+    if (!id_)
+      id_ = provider_->CreateUIResource(this);
+    return id_;
+  }
+
+  // content::UIResourceClient implementation.
+  virtual cc::UIResourceBitmap GetBitmap(cc::UIResourceId uid,
+                                         bool resource_lost) OVERRIDE {
+    DCHECK(!bitmap_.empty());
+    return cc::UIResourceBitmap(bitmap_);
+  }
+
+  // content::UIResourceClientAndroid implementation.
+  virtual void UIResourceIsInvalid() OVERRIDE { id_ = 0; }
+
+  const SkBitmap& bitmap() const { return bitmap_; }
+
+ private:
+  SkBitmap bitmap_;
+  cc::UIResourceId id_;
+  UIResourceProvider* provider_;
+
+  DISALLOW_COPY_AND_ASSIGN(Entry);
+};
+
+SystemUIResourceManagerImpl::SystemUIResourceManagerImpl(
+    UIResourceProvider* ui_resource_provider)
+    : ui_resource_provider_(ui_resource_provider), weak_factory_(this) {
+}
+
+SystemUIResourceManagerImpl::~SystemUIResourceManagerImpl() {
+}
+
+void SystemUIResourceManagerImpl::PreloadResource(ResourceType type) {
+  GetEntry(type);
+}
+
+cc::UIResourceId SystemUIResourceManagerImpl::GetUIResourceId(
+    ResourceType type) {
+  return GetEntry(type)->GetUIResourceId();
+}
+
+SystemUIResourceManagerImpl::Entry* SystemUIResourceManagerImpl::GetEntry(
+    ResourceType type) {
+  DCHECK_GE(type, RESOURCE_TYPE_FIRST);
+  DCHECK_LE(type, RESOURCE_TYPE_LAST);
+  if (!resource_map_[type]) {
+    resource_map_[type].reset(new Entry(ui_resource_provider_));
+    // Lazily build the resource.
+    BuildResource(type);
+  }
+  return resource_map_[type].get();
+}
+
+void SystemUIResourceManagerImpl::BuildResource(ResourceType type) {
+  DCHECK(GetEntry(type)->bitmap().empty());
+
+  // Instead of blocking the main thread, we post a task to load the bitmap.
+  SkBitmap* bitmap = new SkBitmap();
+  base::Closure load_bitmap =
+      base::Bind(&SystemUIResourceManagerImpl::LoadBitmap, type, bitmap);
+  base::Closure finished_load =
+      base::Bind(&SystemUIResourceManagerImpl::OnFinishedLoadBitmap,
+                 weak_factory_.GetWeakPtr(),
+                 type,
+                 base::Owned(bitmap));
+  base::WorkerPool::PostTaskAndReply(
+      FROM_HERE, load_bitmap, finished_load, true);
+}
+
+void SystemUIResourceManagerImpl::LoadBitmap(ResourceType type,
+                                             SkBitmap* bitmap_holder) {
+  SkBitmap bitmap;
+  switch (type) {
+    case ui::SystemUIResourceManager::OVERSCROLL_EDGE:
+      bitmap = gfx::CreateSkBitmapFromAndroidResource(
+          "android:drawable/overscroll_edge", gfx::Size(128, 12));
+      break;
+    case ui::SystemUIResourceManager::OVERSCROLL_GLOW:
+      bitmap = gfx::CreateSkBitmapFromAndroidResource(
+          "android:drawable/overscroll_glow", gfx::Size(128, 64));
+      break;
+  }
+  bitmap.setImmutable();
+  *bitmap_holder = bitmap;
+}
+
+void SystemUIResourceManagerImpl::OnFinishedLoadBitmap(
+    ResourceType type,
+    SkBitmap* bitmap_holder) {
+  DCHECK(bitmap_holder);
+  GetEntry(type)->SetBitmap(*bitmap_holder);
+}
+
+}  // namespace content

content/browser/android/system_ui_resource_manager_impl.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_BROWSER_ANDROID_SYSTEM_UI_RESOURCE_MANAGER_IMPL_H_
+#define CONTENT_BROWSER_ANDROID_SYSTEM_UI_RESOURCE_MANAGER_IMPL_H_
+
+#include "base/basictypes.h"
+#include "base/containers/scoped_ptr_hash_map.h"
+#include "base/memory/weak_ptr.h"
+#include "content/common/content_export.h"
+#include "ui/base/android/system_ui_resource_manager.h"
+
+class SkBitmap;
+
+namespace cc {
+class UIResourceBitmap;
+}
+
+namespace content {
+
+class UIResourceProvider;
+
+class CONTENT_EXPORT SystemUIResourceManagerImpl
+    : public ui::SystemUIResourceManager {
+ public:
+  explicit SystemUIResourceManagerImpl(
+      UIResourceProvider* ui_resource_provider);
+  virtual ~SystemUIResourceManagerImpl();
+
+  virtual void PreloadResource(ResourceType type) OVERRIDE;
+  virtual cc::UIResourceId GetUIResourceId(ResourceType type) OVERRIDE;
+
+ private:
+  friend class TestSystemUIResourceManagerImpl;
+  class Entry;
+
+  // Start loading the resource bitmap.  virtual for testing.
+  virtual void BuildResource(ResourceType type);
+
+  Entry* GetEntry(ResourceType type);
+  static void LoadBitmap(ResourceType, SkBitmap* bitmap_holder);
+  void OnFinishedLoadBitmap(ResourceType, SkBitmap* bitmap_holder);
+
+  scoped_ptr<Entry> resource_map_[RESOURCE_TYPE_LAST + 1];
+  UIResourceProvider* ui_resource_provider_;
+
+  base::WeakPtrFactory<SystemUIResourceManagerImpl> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(SystemUIResourceManagerImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_ANDROID_SYSTEM_UI_RESOURCE_MANAGER_IMPL_H_

content/browser/android/system_ui_resource_manager_impl_unittest.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "cc/resources/ui_resource_bitmap.h"
+#include "content/browser/android/system_ui_resource_manager_impl.h"
+#include "content/public/browser/android/ui_resource_client_android.h"
+#include "content/public/browser/android/ui_resource_provider.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "third_party/skia/include/core/SkCanvas.h"
+
+namespace content {
+
+class TestSystemUIResourceManagerImpl
+    : public content::SystemUIResourceManagerImpl {
+ public:
+  TestSystemUIResourceManagerImpl(content::UIResourceProvider* provider)
+      : SystemUIResourceManagerImpl(provider) {}
+
+  virtual ~TestSystemUIResourceManagerImpl() {}
+
+  virtual void BuildResource(
+      ui::SystemUIResourceManager::ResourceType type) OVERRIDE {}
+
+  void SetResourceAsLoaded(ui::SystemUIResourceManager::ResourceType type) {
+    SkBitmap small_bitmap;
+    SkCanvas canvas(small_bitmap);
+    small_bitmap.allocPixels(
+        SkImageInfo::Make(1, 1, kRGBA_8888_SkColorType, kOpaque_SkAlphaType));
+    canvas.drawColor(SK_ColorWHITE);
+    small_bitmap.setImmutable();
+    OnFinishedLoadBitmap(type, &small_bitmap);
+  }
+};
+
+namespace {
+
+const ui::SystemUIResourceManager::ResourceType TEST_RESOURCE_TYPE =
+    ui::SystemUIResourceManager::OVERSCROLL_GLOW;
+
+class MockUIResourceProvider : public content::UIResourceProvider {
+ public:
+  MockUIResourceProvider()
+      : next_ui_resource_id_(1),
+        has_layer_tree_host_(true),
+        system_ui_resource_manager_(this) {}
+
+  virtual ~MockUIResourceProvider() {}
+
+  virtual cc::UIResourceId CreateUIResource(
+      content::UIResourceClientAndroid* client) OVERRIDE {
+    if (!has_layer_tree_host_)
+      return 0;
+    cc::UIResourceId id = next_ui_resource_id_++;
+    client->GetBitmap(id, false);
+    ui_resource_client_map_[id] = client;
+    return id;
+  }
+
+  virtual void DeleteUIResource(cc::UIResourceId id) OVERRIDE {
+    CHECK(has_layer_tree_host_);
+    ui_resource_client_map_.erase(id);
+  }
+
+  void LayerTreeHostCleared() {
+    has_layer_tree_host_ = false;
+    UIResourceClientMap client_map = ui_resource_client_map_;
+    ui_resource_client_map_.clear();
+    for (UIResourceClientMap::iterator iter = client_map.begin();
+         iter != client_map.end();
+         iter++) {
+      iter->second->UIResourceIsInvalid();
+    }
+  }
+
+  void LayerTreeHostReturned() { has_layer_tree_host_ = true; }
+
+  TestSystemUIResourceManagerImpl& GetSystemUIResourceManager() {
+    return system_ui_resource_manager_;
+  }
+
+  cc::UIResourceId next_ui_resource_id() const { return next_ui_resource_id_; }
+
+ private:
+  typedef base::hash_map<cc::UIResourceId, content::UIResourceClientAndroid*>
+      UIResourceClientMap;
+
+  cc::UIResourceId next_ui_resource_id_;
+  UIResourceClientMap ui_resource_client_map_;
+  bool has_layer_tree_host_;
+
+  // The UIResourceProvider owns the SystemUIResourceManager.
+  TestSystemUIResourceManagerImpl system_ui_resource_manager_;
+};
+
+}  // namespace
+
+class SystemUIResourceManagerImplTest : public testing::Test {
+ public:
+  void PreloadResource(ui::SystemUIResourceManager::ResourceType type) {
+    ui_resource_provider_.GetSystemUIResourceManager().PreloadResource(type);
+  }
+
+  cc::UIResourceId GetUIResourceId(
+      ui::SystemUIResourceManager::ResourceType type) {
+    return ui_resource_provider_.GetSystemUIResourceManager().GetUIResourceId(
+        type);
+  }
+
+  void LayerTreeHostCleared() { ui_resource_provider_.LayerTreeHostCleared(); }
+
+  void LayerTreeHostReturned() {
+    ui_resource_provider_.LayerTreeHostReturned();
+  }
+
+  void SetResourceAsLoaded(ui::SystemUIResourceManager::ResourceType type) {
+    ui_resource_provider_.GetSystemUIResourceManager().SetResourceAsLoaded(
+        type);
+  }
+
+  cc::UIResourceId GetNextUIResourceId() const {
+    return ui_resource_provider_.next_ui_resource_id();
+  }
+
+ private:
+  MockUIResourceProvider ui_resource_provider_;
+};
+
+TEST_F(SystemUIResourceManagerImplTest, GetResourceAfterBitmapLoaded) {
+  SetResourceAsLoaded(TEST_RESOURCE_TYPE);
+  EXPECT_NE(0, GetUIResourceId(TEST_RESOURCE_TYPE));
+}
+
+TEST_F(SystemUIResourceManagerImplTest, GetResourceBeforeLoadBitmap) {
+  EXPECT_EQ(0, GetUIResourceId(TEST_RESOURCE_TYPE));
+  SetResourceAsLoaded(TEST_RESOURCE_TYPE);
+  EXPECT_NE(0, GetUIResourceId(TEST_RESOURCE_TYPE));
+}
+
+TEST_F(SystemUIResourceManagerImplTest, PreloadEnsureResource) {
+  // Preloading the resource should trigger bitmap loading, but the actual
+  // resource id will not be generated until it is explicitly requested.
+  cc::UIResourceId first_resource_id = GetNextUIResourceId();
+  PreloadResource(TEST_RESOURCE_TYPE);
+  SetResourceAsLoaded(TEST_RESOURCE_TYPE);
+  EXPECT_EQ(first_resource_id, GetNextUIResourceId());
+  EXPECT_NE(0, GetUIResourceId(TEST_RESOURCE_TYPE));
+  EXPECT_NE(first_resource_id, GetNextUIResourceId());
+}
+
+TEST_F(SystemUIResourceManagerImplTest, ResetLayerTreeHost) {
+  EXPECT_EQ(0, GetUIResourceId(TEST_RESOURCE_TYPE));
+  LayerTreeHostCleared();
+  EXPECT_EQ(0, GetUIResourceId(TEST_RESOURCE_TYPE));
+  LayerTreeHostReturned();
+  EXPECT_EQ(0, GetUIResourceId(TEST_RESOURCE_TYPE));
+
+  SetResourceAsLoaded(TEST_RESOURCE_TYPE);
+  EXPECT_NE(0, GetUIResourceId(TEST_RESOURCE_TYPE));
+  LayerTreeHostCleared();
+  EXPECT_EQ(0, GetUIResourceId(TEST_RESOURCE_TYPE));
+  LayerTreeHostReturned();
+  EXPECT_NE(0, GetUIResourceId(TEST_RESOURCE_TYPE));
+}
+
+}  // namespace content

content/browser/android/ui_resource_provider_impl.cc

@@ -10,7 +10,8 @@
 
 namespace content {
 
-UIResourceProviderImpl::UIResourceProviderImpl() : host_(NULL) {
+UIResourceProviderImpl::UIResourceProviderImpl()
+    : system_ui_resource_manager_(this), host_(NULL) {
 }
 
 UIResourceProviderImpl::~UIResourceProviderImpl() {
@@ -57,4 +58,9 @@ void UIResourceProviderImpl::DeleteUIResource(cc::UIResourceId ui_resource_id) {
   host_->DeleteUIResource(ui_resource_id);
 }
 
+ui::SystemUIResourceManager&
+UIResourceProviderImpl::GetSystemUIResourceManager() {
+  return system_ui_resource_manager_;
+}
+
 }  // namespace content

content/browser/android/ui_resource_provider_impl.h

@@ -6,6 +6,7 @@
 #define CONTENT_BROWSER_ANDROID_UI_RESOURCE_PROVIDER_IMPL_H_
 
 #include "base/containers/hash_tables.h"
+#include "content/browser/android/system_ui_resource_manager_impl.h"
 #include "content/public/browser/android/ui_resource_provider.h"
 
 namespace cc {
@@ -31,11 +32,13 @@ class UIResourceProviderImpl : public UIResourceProvider {
 
   virtual void DeleteUIResource(cc::UIResourceId resource_id) OVERRIDE;
 
+  ui::SystemUIResourceManager& GetSystemUIResourceManager();
+
  private:
   typedef base::hash_map<cc::UIResourceId, UIResourceClientAndroid*>
       UIResourceClientMap;
   UIResourceClientMap ui_resource_client_map_;
-
+  SystemUIResourceManagerImpl system_ui_resource_manager_;
   cc::LayerTreeHost* host_;
 
   DISALLOW_COPY_AND_ASSIGN(UIResourceProviderImpl);

content/browser/renderer_host/compositor_impl_android.cc

@@ -340,6 +340,10 @@ UIResourceProvider& CompositorImpl::GetUIResourceProvider() {
   return ui_resource_provider_;
 }
 
+ui::SystemUIResourceManager& CompositorImpl::GetSystemUIResourceManager() {
+  return ui_resource_provider_.GetSystemUIResourceManager();
+}
+
 void CompositorImpl::SetRootLayer(scoped_refptr<cc::Layer> root_layer) {
   if (subroot_layer_) {
     subroot_layer_->RemoveFromParent();

content/browser/renderer_host/compositor_impl_android.h

@@ -8,10 +8,8 @@
 #include "base/basictypes.h"
 #include "base/cancelable_callback.h"
 #include "base/compiler_specific.h"
-#include "base/containers/scoped_ptr_hash_map.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
-#include "cc/resources/ui_resource_client.h"
 #include "cc/trees/layer_tree_host_client.h"
 #include "cc/trees/layer_tree_host_single_thread_client.h"
 #include "content/browser/android/ui_resource_provider_impl.h"
@@ -19,6 +17,7 @@
 #include "content/common/content_export.h"
 #include "content/public/browser/android/compositor.h"
 #include "third_party/khronos/GLES2/gl2.h"
+#include "ui/base/android/system_ui_resource_manager.h"
 #include "ui/base/android/window_android_compositor.h"
 
 class SkBitmap;
@@ -98,6 +97,7 @@ class CONTENT_EXPORT CompositorImpl
   virtual void OnVSync(base::TimeTicks frame_time,
                        base::TimeDelta vsync_period) OVERRIDE;
   virtual void SetNeedsAnimate() OVERRIDE;
+  virtual ui::SystemUIResourceManager& GetSystemUIResourceManager() OVERRIDE;
 
   enum CompositingTrigger {
     DO_NOT_COMPOSITE,
@@ -127,9 +127,6 @@ class CONTENT_EXPORT CompositorImpl
     composite_on_vsync_trigger_ = DO_NOT_COMPOSITE;
     will_composite_immediately_ = false;
   }
-  cc::UIResourceId GenerateUIResourceFromUIResourceBitmap(
-      const cc::UIResourceBitmap& bitmap,
-      bool is_transient);
   void OnGpuChannelEstablished();
 
   // root_layer_ is the persistent internal root layer, while subroot_layer_

content/browser/renderer_host/render_widget_host_view_android.cc

@@ -192,7 +192,6 @@ RenderWidgetHostViewAndroid::RenderWidgetHostViewAndroid(
       weak_ptr_factory_(this),
       overscroll_effect_enabled_(!CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kDisableOverscrollEdgeEffect)),
-      overscroll_effect_(OverscrollGlow::Create(overscroll_effect_enabled_)),
       gesture_provider_(CreateGestureProviderConfig(), this),
       gesture_text_selector_(this),
       touch_scrolling_(false),
@@ -368,7 +367,7 @@ void RenderWidgetHostViewAndroid::MovePluginWindows(
 void RenderWidgetHostViewAndroid::Focus() {
   host_->Focus();
   host_->SetInputMethodActive(true);
-  if (overscroll_effect_enabled_)
+  if (overscroll_effect_)
     overscroll_effect_->Enable();
 }
 
@@ -376,6 +375,7 @@ void RenderWidgetHostViewAndroid::Blur() {
   host_->ExecuteEditCommand("Unselect", "");
   host_->SetInputMethodActive(false);
   host_->Blur();
+  if (overscroll_effect_)
     overscroll_effect_->Disable();
 }
 
@@ -929,8 +929,10 @@ void RenderWidgetHostViewAndroid::ComputeContentsSize(
       gfx::Size(texture_size_in_layer_.width() - offset.x(),
                 texture_size_in_layer_.height() - offset.y());
 
+  if (overscroll_effect_) {
     overscroll_effect_->UpdateDisplayParameters(
         CreateOverscrollDisplayParameters(frame_metadata));
+  }
 }
 
 void RenderWidgetHostViewAndroid::InternalSwapCompositorFrame(
@@ -1143,7 +1145,7 @@ void RenderWidgetHostViewAndroid::AttachLayers() {
     return;
 
   content_view_core_->AttachLayer(layer_);
-  if (overscroll_effect_enabled_)
+  if (overscroll_effect_)
     overscroll_effect_->Enable();
   layer_->SetHideLayerAndSubtree(!is_showing_);
 }
@@ -1156,11 +1158,13 @@ void RenderWidgetHostViewAndroid::RemoveLayers() {
     return;
 
   content_view_core_->RemoveLayer(layer_);
+  if (overscroll_effect_)
     overscroll_effect_->Disable();
 }
 
 bool RenderWidgetHostViewAndroid::Animate(base::TimeTicks frame_time) {
-  bool needs_animate = overscroll_effect_->Animate(frame_time);
+  bool needs_animate =
+      overscroll_effect_ ? overscroll_effect_->Animate(frame_time) : false;
   if (selection_controller_)
     needs_animate |= selection_controller_->Animate(frame_time);
   return needs_animate;
@@ -1361,7 +1365,7 @@ void RenderWidgetHostViewAndroid::SendMouseWheelEvent(
 void RenderWidgetHostViewAndroid::SendGestureEvent(
     const blink::WebGestureEvent& event) {
   // Sending a gesture that may trigger overscroll should resume the effect.
-  if (overscroll_effect_enabled_)
+  if (overscroll_effect_)
     overscroll_effect_->Enable();
 
   if (host_)
@@ -1408,7 +1412,9 @@ void RenderWidgetHostViewAndroid::DidOverscroll(
     return;
 
   const float device_scale_factor = content_view_core_->GetDpiScale();
-  if (overscroll_effect_->OnOverscrolled(
+
+  if (overscroll_effect_ &&
+      overscroll_effect_->OnOverscrolled(
           content_view_core_->GetLayer(),
           base::TimeTicks::Now(),
           gfx::ScaleVector2d(params.accumulated_overscroll,
@@ -1475,6 +1481,16 @@ void RenderWidgetHostViewAndroid::SetContentViewCore(
 
   if (!selection_controller_)
     selection_controller_.reset(new TouchSelectionController(this));
+
+  if (!content_view_core_) {
+    overscroll_effect_.reset();
+  } else if (overscroll_effect_enabled_ && !overscroll_effect_) {
+    DCHECK(content_view_core_->GetWindowAndroid()->GetCompositor());
+    overscroll_effect_ =
+        OverscrollGlow::Create(&content_view_core_->GetWindowAndroid()
+                                    ->GetCompositor()
+                                    ->GetSystemUIResourceManager());
+  }
 }
 
 void RenderWidgetHostViewAndroid::RunAckCallbacks() {

content/browser/renderer_host/render_widget_host_view_android.h

@@ -355,7 +355,6 @@ class CONTENT_EXPORT RenderWidgetHostViewAndroid
 
   const bool overscroll_effect_enabled_;
   // Used to render overscroll overlays.
-  // Note: |overscroll_effect_| will never be NULL, even if it's never enabled.
   scoped_ptr<OverscrollGlow> overscroll_effect_;
 
   // Provides gesture synthesis given a stream of touch events (derived from

content/content_browser.gypi

@@ -313,6 +313,8 @@
       'browser/android/popup_touch_handle_drawable.h',
       'browser/android/surface_texture_peer_browser_impl.cc',
       'browser/android/surface_texture_peer_browser_impl.h',
+      'browser/android/system_ui_resource_manager_impl.cc',
+      'browser/android/system_ui_resource_manager_impl.h',
       'browser/android/tracing_controller_android.cc',
       'browser/android/tracing_controller_android.h',
       'browser/android/web_contents_observer_android.cc',

content/content_tests.gypi

@@ -901,6 +901,7 @@
             'browser/android/java/gin_java_method_invocation_helper_unittest.cc',
             'browser/android/java/java_type_unittest.cc',
             'browser/android/java/jni_helper_unittest.cc',
+            'browser/android/system_ui_resource_manager_impl_unittest.cc',
             'renderer/java/gin_java_bridge_value_converter_unittest.cc',
           ],
           'sources!': [

ui/base/BUILD.gn

@@ -21,6 +21,7 @@ component("base") {
     "accelerators/platform_accelerator.h",
     "accelerators/platform_accelerator_cocoa.h",
     "accelerators/platform_accelerator_cocoa.mm",
+    "android/system_ui_resource_manager.h",
     "android/ui_base_jni_registrar.cc",
     "android/ui_base_jni_registrar.h",
     "android/view_android.cc",

ui/base/android/system_ui_resource_manager.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UI_BASE_ANDROID_SYSTEM_UI_RESOURCE_MANAGER_H_
+#define UI_BASE_ANDROID_SYSTEM_UI_RESOURCE_MANAGER_H_
+
+#include "cc/resources/ui_resource_client.h"
+#include "ui/base/ui_base_export.h"
+
+namespace ui {
+
+// Interface for loading and accessing shared system UI resources.
+class UI_BASE_EXPORT SystemUIResourceManager {
+ public:
+  enum ResourceType {
+    OVERSCROLL_EDGE = 0,
+    OVERSCROLL_GLOW,
+    RESOURCE_TYPE_FIRST = OVERSCROLL_EDGE,
+    RESOURCE_TYPE_LAST = OVERSCROLL_GLOW
+  };
+
+  virtual ~SystemUIResourceManager() {}
+
+  // Optionally trigger bitmap loading for a given |resource|, if necessary.
+  // Note that this operation may be asynchronous, and subsequent queries to
+  // |GetUIResourceId()| will yield a valid result only after loading finishes.
+  // This method is particularly useful for idly loading a resource before an
+  // explicit cc::UIResourceId is required. Repeated calls will be ignored.
+  virtual void PreloadResource(ResourceType resource) = 0;
+
+  // Return the resource id associated with |resource|. If loading hasn't yet
+  // begun for the given |resource|, it will be triggered immediately. If
+  // loading is asynchronous, 0 will be returned until loading has finished, and
+  // the caller is responsible for re-querying until a valid id is returned.
+  virtual cc::UIResourceId GetUIResourceId(ResourceType resource) = 0;
+};
+
+}  // namespace ui
+
+#endif  // UI_BASE_ANDROID_SYSTEM_UI_RESOURCE_MANAGER_H_

ui/base/android/window_android_compositor.h

@@ -6,6 +6,7 @@
 #define UI_BASE_ANDROID_WINDOW_ANDROID_COMPOSITOR_H_
 
 #include "cc/output/copy_output_request.h"
+#include "ui/base/android/system_ui_resource_manager.h"
 #include "ui/base/ui_base_export.h"
 
 namespace cc {
@@ -25,6 +26,7 @@ class UI_BASE_EXPORT WindowAndroidCompositor {
   virtual void OnVSync(base::TimeTicks frame_time,
                        base::TimeDelta vsync_period) = 0;
   virtual void SetNeedsAnimate() = 0;
+  virtual SystemUIResourceManager& GetSystemUIResourceManager() = 0;
 };
 
 }  // namespace ui

ui/base/ui_base.gyp

@@ -47,6 +47,7 @@
         'accelerators/platform_accelerator.h',
         'accelerators/platform_accelerator_cocoa.h',
         'accelerators/platform_accelerator_cocoa.mm',
+        'android/system_ui_resource_manager.h',
         'android/ui_base_jni_registrar.cc',
         'android/ui_base_jni_registrar.h',
         'android/view_android.cc',

ui/gfx/android/java_bitmap.cc

@@ -9,6 +9,7 @@
 #include "base/android/jni_string.h"
 #include "base/logging.h"
 #include "jni/BitmapHelper_jni.h"
+#include "skia/ext/image_operations.h"
 #include "ui/gfx/size.h"
 
 using base::android::AttachCurrentThread;
@@ -68,17 +69,6 @@ ScopedJavaLocalRef<jobject> CreateJavaBitmap(int width,
       AttachCurrentThread(), width, height, java_bitmap_config);
 }
 
-ScopedJavaLocalRef<jobject> CreateJavaBitmapFromAndroidResource(
-    const char* name,
-    gfx::Size size) {
-  DCHECK(name);
-  DCHECK(!size.IsEmpty());
-  JNIEnv* env = AttachCurrentThread();
-  ScopedJavaLocalRef<jstring> jname(ConvertUTF8ToJavaString(env, name));
-  return Java_BitmapHelper_decodeDrawableResource(
-      env, jname.obj(), size.width(), size.height());
-}
-
 ScopedJavaLocalRef<jobject> ConvertToJavaBitmap(const SkBitmap* skbitmap) {
   DCHECK(skbitmap);
   DCHECK(!skbitmap->isNull());
@@ -96,6 +86,26 @@ ScopedJavaLocalRef<jobject> ConvertToJavaBitmap(const SkBitmap* skbitmap) {
   return jbitmap;
 }
 
+SkBitmap CreateSkBitmapFromAndroidResource(const char* name, gfx::Size size) {
+  DCHECK(name);
+  DCHECK(!size.IsEmpty());
+  JNIEnv* env = AttachCurrentThread();
+  ScopedJavaLocalRef<jstring> jname(ConvertUTF8ToJavaString(env, name));
+  base::android::ScopedJavaLocalRef<jobject> jobj =
+      Java_BitmapHelper_decodeDrawableResource(
+          env, jname.obj(), size.width(), size.height());
+
+  if (jobj.is_null())
+    return SkBitmap();
+
+  SkBitmap bitmap = CreateSkBitmapFromJavaBitmap(gfx::JavaBitmap(jobj.obj()));
+  if (bitmap.isNull())
+    return bitmap;
+
+  return skia::ImageOperations::Resize(
+      bitmap, skia::ImageOperations::RESIZE_BOX, size.width(), size.height());
+}
+
 SkBitmap CreateSkBitmapFromJavaBitmap(const JavaBitmap& jbitmap) {
   // TODO(jdduke): Convert to DCHECK's when sufficient data has been capture for
   // crbug.com/341406.

ui/gfx/android/java_bitmap.h

@@ -57,12 +57,12 @@ GFX_EXPORT base::android::ScopedJavaLocalRef<jobject> CreateJavaBitmap(
     int height,
     SkColorType color_type);
 
-// Loads a Java-backed bitmap (android.graphics.Bitmap) from the provided
-// drawable resource identifier (e.g., android:drawable/overscroll_glow). If the
-// resource loads successfully, it will be integrally scaled down, preserving
-// aspect ratio, to a size no smaller than |size|. Otherwise, null is returned.
-GFX_EXPORT base::android::ScopedJavaLocalRef<jobject>
-    CreateJavaBitmapFromAndroidResource(const char* name, gfx::Size size);
+// Loads an SkBitmap from the provided drawable resource identifier (e.g.,
+// android:drawable/overscroll_glow). If the resource loads successfully, it
+// will be integrally scaled down, preserving aspect ratio, to a size no smaller
+// than |size|. Otherwise, an empty bitmap is returned.
+GFX_EXPORT SkBitmap
+    CreateSkBitmapFromAndroidResource(const char* name, gfx::Size size);
 
 // Converts |skbitmap| to a Java-backed bitmap (android.graphics.Bitmap).
 // Note: |skbitmap| is assumed to be non-null, non-empty and one of RGBA_8888 or