[Android WebView] OnMemoryPressure to drop tile memory

In OnMemoryPressure, drop tiles on invisible browser views.

Not reusing base::MemoryPressureListener because Android
WebView requires onTrimMemory to be called synchronously.

BUG=
NOTRY=true

Review URL: https://codereview.chromium.org/25082006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226643 0039d316-1c4b-4281-b951-d872f2087c98

android_webview/browser/browser_view_renderer.h

@@ -140,6 +140,9 @@ class BrowserViewRenderer {
   virtual bool IsVisible() = 0;
   virtual gfx::Rect GetScreenRect() = 0;
 
+  // ComponentCallbacks2.onTrimMemory callback.
+  virtual void TrimMemory(int level) = 0;
+
   virtual ~BrowserViewRenderer() {}
 };
 

android_webview/browser/in_process_view_renderer.cc

@@ -19,7 +19,6 @@
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
-#include "content/public/browser/android/synchronous_compositor.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/content_switches.h"
@@ -316,6 +315,65 @@ bool InProcessViewRenderer::RequestProcessGL() {
   return client_->RequestDrawGL(NULL);
 }
 
+void InProcessViewRenderer::TrimMemory(int level) {
+  // Constants from Android ComponentCallbacks2.
+  enum {
+    TRIM_MEMORY_RUNNING_LOW = 10,
+    TRIM_MEMORY_UI_HIDDEN = 20,
+    TRIM_MEMORY_BACKGROUND = 40,
+  };
+
+  // Not urgent enough. TRIM_MEMORY_UI_HIDDEN is treated specially because
+  // it does not indicate memory pressure, but merely that the app is
+  // backgrounded.
+  if (level < TRIM_MEMORY_RUNNING_LOW || level == TRIM_MEMORY_UI_HIDDEN)
+    return;
+
+  // Nothing to drop.
+  if (!attached_to_window_ || !hardware_initialized_ || !compositor_)
+    return;
+
+  // Do not release resources on view we expect to get DrawGL soon.
+  if (level < TRIM_MEMORY_BACKGROUND) {
+    client_->UpdateGlobalVisibleRect();
+    if (view_visible_ && window_visible_ &&
+        !cached_global_visible_rect_.IsEmpty()) {
+      return;
+    }
+  }
+
+  if (!eglGetCurrentContext()) {
+    NOTREACHED();
+    return;
+  }
+
+  // Just set the memory limit to 0 and drop all tiles. This will be reset to
+  // normal levels in the next DrawGL call.
+  content::SynchronousCompositorMemoryPolicy policy;
+  policy.bytes_limit = 0;
+  policy.num_resources_limit = 0;
+  if (memory_policy_ == policy)
+    return;
+
+  TRACE_EVENT0("android_webview", "InProcessViewRenderer::TrimMemory");
+  ScopedAppGLStateRestore state_restore(
+      ScopedAppGLStateRestore::MODE_RESOURCE_MANAGEMENT);
+  gpu::InProcessCommandBuffer::ProcessGpuWorkOnCurrentThread();
+  ScopedAllowGL allow_gl;
+
+  SetMemoryPolicy(policy);
+  ForceFakeCompositeSW();
+}
+
+void InProcessViewRenderer::SetMemoryPolicy(
+    content::SynchronousCompositorMemoryPolicy& new_policy) {
+  if (memory_policy_ == new_policy)
+    return;
+
+  memory_policy_ = new_policy;
+  compositor_->SetMemoryPolicy(memory_policy_);
+}
+
 void InProcessViewRenderer::UpdateCachedGlobalVisibleRect() {
   client_->UpdateGlobalVisibleRect();
 }
@@ -423,7 +481,7 @@ void InProcessViewRenderer::DrawGL(AwDrawGLInfo* draw_info) {
   policy.bytes_limit =
       (policy.bytes_limit / kMemoryAllocationStep + 1) * kMemoryAllocationStep;
   policy.num_resources_limit = kMaxNumTilesToFillDisplay * g_memory_multiplier;
-  compositor_->SetMemoryPolicy(policy);
+  SetMemoryPolicy(policy);
 
   DCHECK(gl_surface_);
   gl_surface_->SetBackingFrameBufferObject(
@@ -638,7 +696,7 @@ void InProcessViewRenderer::OnDetachedFromWindow() {
     DCHECK(compositor_);
 
     ScopedAppGLStateRestore state_restore(
-        ScopedAppGLStateRestore::MODE_DETACH_FROM_WINDOW);
+        ScopedAppGLStateRestore::MODE_RESOURCE_MANAGEMENT);
     gpu::InProcessCommandBuffer::ProcessGpuWorkOnCurrentThread();
     ScopedAllowGL allow_gl;
     compositor_->ReleaseHwDraw();
@@ -869,11 +927,15 @@ void InProcessViewRenderer::FallbackTickFired() {
   // This should only be called if OnDraw or DrawGL did not come in time, which
   // means block_invalidates_ must still be true.
   DCHECK(block_invalidates_);
-  if (compositor_needs_continuous_invalidate_ && compositor_) {
+  if (compositor_needs_continuous_invalidate_ && compositor_)
+    ForceFakeCompositeSW();
+}
+
+void InProcessViewRenderer::ForceFakeCompositeSW() {
+  DCHECK(compositor_);
   SkBitmapDevice device(SkBitmap::kARGB_8888_Config, 1, 1);
   SkCanvas canvas(&device);
   CompositeSW(&canvas);
-  }
 }
 
 bool InProcessViewRenderer::CompositeSW(SkCanvas* canvas) {

android_webview/browser/in_process_view_renderer.h

@@ -10,6 +10,7 @@
 #include "android_webview/browser/browser_view_renderer.h"
 #include "android_webview/browser/gl_view_renderer_manager.h"
 #include "base/cancelable_callback.h"
+#include "content/public/browser/android/synchronous_compositor.h"
 #include "content/public/browser/android/synchronous_compositor_client.h"
 #include "ui/gfx/vector2d_f.h"
 
@@ -71,6 +72,7 @@ class InProcessViewRenderer : public BrowserViewRenderer,
   virtual bool IsAttachedToWindow() OVERRIDE;
   virtual bool IsVisible() OVERRIDE;
   virtual gfx::Rect GetScreenRect() OVERRIDE;
+  virtual void TrimMemory(int level) OVERRIDE;
 
   // SynchronousCompositorClient overrides
   virtual void DidInitializeCompositor(
@@ -108,6 +110,7 @@ class InProcessViewRenderer : public BrowserViewRenderer,
   // If we call up view invalidate and OnDraw is not called before a deadline,
   // then we keep ticking the SynchronousCompositor so it can make progress.
   void FallbackTickFired();
+  void ForceFakeCompositeSW();
 
   void NoLongerExpectsDrawGL();
 
@@ -115,6 +118,8 @@ class InProcessViewRenderer : public BrowserViewRenderer,
 
   gfx::Vector2d max_scroll_offset() const;
 
+  void SetMemoryPolicy(content::SynchronousCompositorMemoryPolicy& new_policy);
+
   // For debug tracing or logging. Return the string representation of this
   // view renderer's state and the |draw_info| if provided.
   std::string ToString(AwDrawGLInfo* draw_info) const;
@@ -176,6 +181,8 @@ class InProcessViewRenderer : public BrowserViewRenderer,
 
   GLViewRendererManager::Key manager_key_;
 
+  content::SynchronousCompositorMemoryPolicy memory_policy_;
+
   DISALLOW_COPY_AND_ASSIGN(InProcessViewRenderer);
 };
 

android_webview/browser/scoped_app_gl_state_restore.cc

@@ -64,7 +64,7 @@ ScopedAppGLStateRestore::ScopedAppGLStateRestore(CallMode mode) : mode_(mode) {
       DCHECK_EQ(0, vertex_array_buffer_binding_);
       DCHECK_EQ(0, index_array_buffer_binding_);
       break;
-    case MODE_DETACH_FROM_WINDOW:
+    case MODE_RESOURCE_MANAGEMENT:
       glGetBooleanv(GL_BLEND, &blend_enabled_);
       glGetIntegerv(GL_BLEND_SRC_RGB, &blend_src_rgb_);
       glGetIntegerv(GL_BLEND_SRC_ALPHA, &blend_src_alpha_);
@@ -205,7 +205,11 @@ ScopedAppGLStateRestore::~ScopedAppGLStateRestore() {
                   enable_sample_alpha_to_coverage_);
   GLEnableDisable(GL_SAMPLE_COVERAGE, enable_sample_coverage_);
 
-  if (mode_ == MODE_DETACH_FROM_WINDOW) {
+  switch(mode_) {
+    case MODE_DRAW:
+      // No-op.
+      break;
+    case MODE_RESOURCE_MANAGEMENT:
       GLEnableDisable(GL_BLEND, blend_enabled_);
       glBlendFuncSeparate(
           blend_src_rgb_, blend_dest_rgb_, blend_src_alpha_, blend_dest_alpha_);
@@ -216,6 +220,7 @@ ScopedAppGLStateRestore::~ScopedAppGLStateRestore() {
 
       glScissor(
           scissor_box_[0], scissor_box_[1], scissor_box_[2], scissor_box_[3]);
+      break;
   }
 
   GLEnableDisable(GL_STENCIL_TEST, stencil_test_);

android_webview/browser/scoped_app_gl_state_restore.h

@@ -18,7 +18,7 @@ class ScopedAppGLStateRestore {
  public:
   enum CallMode {
     MODE_DRAW,
-    MODE_DETACH_FROM_WINDOW
+    MODE_RESOURCE_MANAGEMENT,
   };
 
   ScopedAppGLStateRestore(CallMode mode);

android_webview/java/src/org/chromium/android_webview/AwContents.java

@@ -4,6 +4,8 @@
 
 package org.chromium.android_webview;
 
+import android.content.ComponentCallbacks2;
+import android.content.Context;
 import android.content.pm.PackageManager;
 import android.content.res.Configuration;
 import android.graphics.Bitmap;
@@ -193,6 +195,8 @@ public class AwContents {
 
     private AwAutofillManagerDelegate mAwAutofillManagerDelegate;
 
+    private ComponentCallbacks2 mComponentCallbacks;
+
     private static final class DestroyRunnable implements Runnable {
         private int mNativeAwContents;
         private DestroyRunnable(int nativeAwContents) {
@@ -431,6 +435,22 @@ public class AwContents {
         }
     }
 
+    private class AwComponentCallbacks implements ComponentCallbacks2 {
+          @Override
+          public void onTrimMemory(int level) {
+              if (mNativeAwContents == 0) return;
+              nativeTrimMemory(mNativeAwContents, level);
+          }
+
+          @Override
+          public void onLowMemory() {
+          }
+
+          @Override
+          public void onConfigurationChanged(Configuration configuration) {
+          }
+    };
+
     /**
      * @param browserContext the browsing context to associate this view contents with.
      * @param containerView the view-hierarchy item this object will be bound to.
@@ -1480,6 +1500,10 @@ public class AwContents {
         mContentViewCore.onAttachedToWindow();
         nativeOnAttachedToWindow(mNativeAwContents, mContainerView.getWidth(),
                 mContainerView.getHeight());
+
+        if (mComponentCallbacks != null) return;
+        mComponentCallbacks = new AwComponentCallbacks();
+        mContainerView.getContext().registerComponentCallbacks(mComponentCallbacks);
     }
 
     /**
@@ -1494,6 +1518,11 @@ public class AwContents {
 
         mContentViewCore.onDetachedFromWindow();
 
+        if (mComponentCallbacks != null) {
+          mContainerView.getContext().unregisterComponentCallbacks(mComponentCallbacks);
+          mComponentCallbacks = null;
+        }
+
         if (mPendingDetachCleanupReferences != null) {
             for (int i = 0; i < mPendingDetachCleanupReferences.size(); ++i) {
                 mPendingDetachCleanupReferences.get(i).cleanupNow();
@@ -1967,4 +1996,6 @@ public class AwContents {
             int nativeAwContents, boolean value, String requestingFrame);
 
     private native void nativeSetJsOnlineProperty(int nativeAwContents, boolean networkUp);
+
+    private native void nativeTrimMemory(int nativeAwContents, int level);
 }

android_webview/native/aw_contents.cc

@@ -898,4 +898,8 @@ void AwContents::SetJsOnlineProperty(JNIEnv* env,
   render_view_host_ext_->SetJsOnlineProperty(network_up);
 }
 
+void AwContents::TrimMemory(JNIEnv* env, jobject obj, jint level) {
+  browser_view_renderer_->TrimMemory(level);
+}
+
 }  // namespace android_webview

android_webview/native/aw_contents.h

@@ -179,6 +179,7 @@ class AwContents : public FindHelper::Listener,
   void SetAwAutofillManagerDelegate(jobject delegate);
 
   void SetJsOnlineProperty(JNIEnv* env, jobject obj, jboolean network_up);
+  void TrimMemory(JNIEnv* env, jobject obj, jint level);
 
  private:
   void InitAutofillIfNecessary(bool enabled);

content/public/browser/android/synchronous_compositor.cc

@@ -9,4 +9,15 @@ namespace content {
 SynchronousCompositorMemoryPolicy::SynchronousCompositorMemoryPolicy()
     : bytes_limit(0), num_resources_limit(0) {}
 
+bool SynchronousCompositorMemoryPolicy::operator==(
+    const SynchronousCompositorMemoryPolicy& other) const {
+  return bytes_limit == other.bytes_limit &&
+      num_resources_limit == other.num_resources_limit;
+}
+
+bool SynchronousCompositorMemoryPolicy::operator!=(
+    const SynchronousCompositorMemoryPolicy& other) const {
+  return !(*this == other);
+}
+
 }  // namespace content

content/public/browser/android/synchronous_compositor.h

@@ -31,6 +31,9 @@ struct CONTENT_EXPORT SynchronousCompositorMemoryPolicy {
   size_t num_resources_limit;
 
   SynchronousCompositorMemoryPolicy();
+
+  bool operator==(const SynchronousCompositorMemoryPolicy& other) const;
+  bool operator!=(const SynchronousCompositorMemoryPolicy& other) const;
 };
 
 // Interface for embedders that wish to direct compositing operations