Plumbing for layout rectangle debug info. Companion to

https://code.google.com/p/chromium/issues/detail?id=314945

Patch from Chris Harrelson <chrishtr@gmail.com>

BUG=314945
..


..


Plumbing for for layout rectangle debug information.

BUG=

Review URL: https://codereview.chromium.org/61883006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238297 0039d316-1c4b-4281-b951-d872f2087c98

AUTHORS

@@ -52,6 +52,7 @@ Chamal De Silva <chamalsl@yahoo.com>
 Chandra Shekar Vallala <brk376@motorola.com>
 Changbin Shao <changbin.shao@intel.com>
 Chaobin Zhang <zhchbin@gmail.com>
+Chris Harrelson <chrishtr@gmail.com>
 Christophe Dumez <ch.dumez@samsung.com>
 Christopher Dale <chrelad@gmail.com>
 Clemens Fruhwirth <clemens@endorphin.org>

cc/layers/layer.cc

@@ -876,10 +876,12 @@ void Layer::PushPropertiesTo(LayerImpl* layer) {
   bool is_tracing;
   TRACE_EVENT_CATEGORY_GROUP_ENABLED(TRACE_DISABLED_BY_DEFAULT("cc.debug"),
                                      &is_tracing);
-  if (is_tracing)
-      layer->SetDebugName(DebugName());
-  else
-      layer->SetDebugName(std::string());
+  if (is_tracing) {
+    layer->SetDebugName(DebugName());
+    layer->SetDebugInfo(TakeDebugInfo());
+  } else {
+    layer->SetDebugName(std::string());
+  }
 
   layer->SetCompositingReasons(compositing_reasons_);
   layer->SetDoubleSided(double_sided_);
@@ -1037,6 +1039,14 @@ std::string Layer::DebugName() {
   return client_ ? client_->DebugName() : std::string();
 }
 
+scoped_refptr<base::debug::ConvertableToTraceFormat> Layer::TakeDebugInfo() {
+  if (client_)
+    return client_->TakeDebugInfo();
+  else
+    return NULL;
+}
+
+
 void Layer::SetCompositingReasons(CompositingReasons reasons) {
   compositing_reasons_ = reasons;
 }

cc/layers/layer.h

@@ -39,6 +39,12 @@ namespace gfx {
 class BoxF;
 }
 
+namespace base {
+namespace debug {
+class ConvertableToTraceFormat;
+}
+}
+
 namespace cc {
 
 class Animation;
@@ -358,6 +364,7 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
   virtual void OnOutputSurfaceCreated() {}
 
   virtual std::string DebugName();
+  virtual scoped_refptr<base::debug::ConvertableToTraceFormat> TakeDebugInfo();
 
   void SetLayerClient(LayerClient* client) { client_ = client; }
 

cc/layers/layer_client.h

@@ -7,14 +7,27 @@
 
 #include <string>
 
+#include "base/memory/ref_counted.h"
 #include "cc/base/cc_export.h"
 
+namespace base {
+namespace debug {
+class ConvertableToTraceFormat;
+}
+}
+
 namespace cc {
 
 class CC_EXPORT LayerClient {
  public:
   virtual std::string DebugName() = 0;
 
+  // Returns a pointer to a debug info object, if one has been computed.
+  // If not, returns NULL. If the returned pointer is non-NULL, the caller takes
+  // ownership of the pointer.
+  virtual scoped_refptr<base::debug::ConvertableToTraceFormat>
+      TakeDebugInfo() = 0;
+
  protected:
   virtual ~LayerClient() {}
 };

cc/layers/layer_impl.cc

@@ -5,6 +5,7 @@
 #include "cc/layers/layer_impl.h"
 
 #include "base/debug/trace_event.h"
+#include "base/json/json_reader.h"
 #include "base/strings/stringprintf.h"
 #include "cc/animation/animation_registrar.h"
 #include "cc/animation/scrollbar_animation_controller.h"
@@ -159,6 +160,11 @@ void LayerImpl::SetScrollParent(LayerImpl* parent) {
   scroll_parent_ = parent;
 }
 
+void LayerImpl::SetDebugInfo(
+    scoped_refptr<base::debug::ConvertableToTraceFormat> other) {
+  debug_info_ = other;
+}
+
 void LayerImpl::SetScrollChildren(std::set<LayerImpl*>* children) {
   if (scroll_children_.get() == children)
     return;
@@ -594,6 +600,8 @@ void LayerImpl::PushPropertiesTo(LayerImpl* layer) {
   // Reset any state that should be cleared for the next update.
   stacking_order_changed_ = false;
   update_rect_ = gfx::RectF();
+
+  layer->SetDebugInfo(debug_info_);
 }
 
 base::DictionaryValue* LayerImpl::LayerTreeAsJson() const {
@@ -1384,6 +1392,19 @@ void LayerImpl::AsValueInto(base::DictionaryValue* state) const {
     if (layer_animation_controller_->AnimatedBoundsForBox(box, &inflated))
       state->Set("animated_bounds", MathUtil::AsValue(inflated).release());
   }
+
+  if (debug_info_.get()) {
+    std::string str;
+    debug_info_->AppendAsTraceFormat(&str);
+    base::JSONReader json_reader;
+    // Parsing the JSON and re-encoding it is not very efficient,
+    // but it's the simplest way to achieve the desired effect, which
+    // is to output:
+    // {..., layout_rects: [{geometry_rect: ...}, ...], ...}
+    // rather than:
+    // {layout_rects: "[{geometry_rect: ...}, ...]", ...}
+    state->Set("layout_rects", json_reader.ReadToValue(str));
+  }
 }
 
 size_t LayerImpl::GPUMemoryUsageInBytes() const { return 0; }

cc/layers/layer_impl.h

@@ -36,6 +36,10 @@
 #include "ui/gfx/transform.h"
 
 namespace base {
+namespace debug {
+class ConvertableToTraceFormat;
+}
+
 class DictionaryValue;
 }
 
@@ -511,6 +515,9 @@ class CC_EXPORT LayerImpl : public LayerAnimationValueObserver,
 
   virtual void RunMicroBenchmark(MicroBenchmarkImpl* benchmark);
 
+  virtual void SetDebugInfo(
+      scoped_refptr<base::debug::ConvertableToTraceFormat> other);
+
  protected:
   LayerImpl(LayerTreeImpl* layer_impl, int id);
 
@@ -651,6 +658,8 @@ class CC_EXPORT LayerImpl : public LayerAnimationValueObserver,
   // hierarchy before layers can be drawn.
   DrawProperties<LayerImpl> draw_properties_;
 
+  scoped_refptr<base::debug::ConvertableToTraceFormat> debug_info_;
+
   DISALLOW_COPY_AND_ASSIGN(LayerImpl);
 };
 

ui/compositor/layer.cc

@@ -667,6 +667,11 @@ std::string Layer::DebugName() {
   return name_;
 }
 
+scoped_refptr<base::debug::ConvertableToTraceFormat> Layer::TakeDebugInfo() {
+  // TODO: return something useful here.
+  return NULL;
+}
+
 void Layer::OnAnimationStarted(const cc::AnimationEvent& event) {
   if (animator_.get())
     animator_->OnThreadedAnimationStarted(event);

ui/compositor/layer.h

@@ -336,6 +336,9 @@ class COMPOSITOR_EXPORT Layer
   // LayerClient
   virtual std::string DebugName() OVERRIDE;
 
+  virtual scoped_refptr<base::debug::ConvertableToTraceFormat>
+      TakeDebugInfo() OVERRIDE;
+
   // LayerAnimationEventObserver
   virtual void OnAnimationStarted(const cc::AnimationEvent& event) OVERRIDE;
 

webkit/renderer/compositor_bindings/web_layer_impl.cc

@@ -5,7 +5,9 @@
 #include "webkit/renderer/compositor_bindings/web_layer_impl.h"
 
 #include "base/bind.h"
+#include "base/debug/trace_event_impl.h"
 #include "base/strings/string_util.h"
+#include "base/threading/thread_checker.h"
 #include "cc/animation/animation.h"
 #include "cc/base/region.h"
 #include "cc/layers/layer.h"
@@ -13,6 +15,7 @@
 #include "third_party/WebKit/public/platform/WebCompositingReasons.h"
 #include "third_party/WebKit/public/platform/WebFloatPoint.h"
 #include "third_party/WebKit/public/platform/WebFloatRect.h"
+#include "third_party/WebKit/public/platform/WebGraphicsLayerDebugInfo.h"
 #include "third_party/WebKit/public/platform/WebLayerClient.h"
 #include "third_party/WebKit/public/platform/WebLayerPositionConstraint.h"
 #include "third_party/WebKit/public/platform/WebLayerScrollClient.h"
@@ -372,6 +375,37 @@ void WebLayerImpl::setWebLayerClient(blink::WebLayerClient* client) {
   web_layer_client_ = client;
 }
 
+// TODO(chrishtr): move DebugName into this class.
+class TracedDebugInfo : public base::debug::ConvertableToTraceFormat {
+ public:
+  // This object takes ownership of the debug_info object.
+  explicit TracedDebugInfo(blink::WebGraphicsLayerDebugInfo* debug_info) :
+    debug_info_(debug_info) {}
+  virtual void AppendAsTraceFormat(std::string* out) const OVERRIDE {
+    DCHECK(thread_checker_.CalledOnValidThread());
+    blink::WebString web_string;
+    debug_info_->appendAsTraceFormat(&web_string);
+    out->append(web_string.utf8());
+  }
+ private:
+  virtual ~TracedDebugInfo() {}
+  scoped_ptr<blink::WebGraphicsLayerDebugInfo> debug_info_;
+  base::ThreadChecker thread_checker_;
+};
+
+scoped_refptr<base::debug::ConvertableToTraceFormat>
+    WebLayerImpl::TakeDebugInfo() {
+  if (!web_layer_client_)
+    return NULL;
+  blink::WebGraphicsLayerDebugInfo* debug_info =
+      web_layer_client_->takeDebugInfo();
+
+  if (debug_info)
+    return new TracedDebugInfo(debug_info);
+  else
+    return NULL;
+}
+
 std::string WebLayerImpl::DebugName() {
   if (!web_layer_client_)
     return std::string();

webkit/renderer/compositor_bindings/web_layer_impl.h

@@ -35,6 +35,12 @@ class WebLayerClient;
 struct WebFloatRect;
 }
 
+namespace base {
+namespace debug {
+class ConvertableToTraceFormat;
+}
+}
+
 namespace webkit {
 
 class WebToCCAnimationDelegateAdapter;
@@ -125,6 +131,8 @@ class WebLayerImpl : public blink::WebLayer, public cc::LayerClient {
 
   // LayerClient implementation.
   virtual std::string DebugName() OVERRIDE;
+  virtual scoped_refptr<base::debug::ConvertableToTraceFormat>
+      TakeDebugInfo() OVERRIDE;
 
   virtual void setScrollParent(blink::WebLayer* parent);
   virtual void setClipParent(blink::WebLayer* parent);