cc: Changed picture clones to emit an alias trace.

This patch changes the tracing snapshot code for pictures to emit a
much smaller message for picture clones. The regular picture message
looks like the following:

{
  params: {
   layer_rect: { ... },
   opaque_rect: { ... },
  },
  skp64: { /* large chunk here */ }
}

That message is generated for both the original picture and its clones.

The format for the original picture stays the same, but the clone
message becomes the following:

{
  alias: { id_ref: { /* id of the original */ } }
}

This change has to be accompanied by a small change to trace-viewer
to handle the new message correctly.

Note this also includes a trace-viewer DEPS roll.

R=nduca@chromium.org

Review URL: https://chromiumcodereview.appspot.com/23717012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@221102 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 46 insertions, 2 deletions

diff --git a/cc/debug/traced_picture.cc b/cc/debug/traced_picture.cc
index 7f04d0d..0cc2148 100644
--- a/cc/debug/traced_picture.cc
+++ b/cc/debug/traced_picture.cc
@@ -12,7 +12,8 @@
 namespace cc {
 
 TracedPicture::TracedPicture(scoped_refptr<Picture> picture)
-  : picture_(picture) {
+  : picture_(picture),
+    is_alias_(false) {
 }
 
 TracedPicture::~TracedPicture() {
@@ -25,7 +26,34 @@ scoped_ptr<base::debug::ConvertableToTraceFormat>
   return result.PassAs<base::debug::ConvertableToTraceFormat>();
 }
 
+scoped_ptr<base::debug::ConvertableToTraceFormat>
+    TracedPicture::AsTraceablePictureAlias(Picture* original) {
+  TracedPicture* ptr = new TracedPicture(original);
+  ptr->is_alias_ = true;
+  scoped_ptr<TracedPicture> result(ptr);
+  return result.PassAs<base::debug::ConvertableToTraceFormat>();
+}
+
 void TracedPicture::AppendAsTraceFormat(std::string* out) const {
+  if (is_alias_)
+    AppendPictureAlias(out);
+  else
+    AppendPicture(out);
+}
+
+void TracedPicture::AppendPictureAlias(std::string* out) const {
+  scoped_ptr<base::DictionaryValue> alias(new base::DictionaryValue());
+  alias->SetString("id_ref", base::StringPrintf("%p", picture_.get()));
+
+  scoped_ptr<base::DictionaryValue> res(new base::DictionaryValue());
+  res->Set("alias", alias.release());
+
+  std::string tmp;
+  base::JSONWriter::Write(res.get(), &tmp);
+  out->append(tmp);
+}
+
+void TracedPicture::AppendPicture(std::string* out) const {
   scoped_ptr<base::Value> value = picture_->AsValue();
   std::string tmp;
   base::JSONWriter::Write(value.get(), &tmp);
diff --git a/cc/debug/traced_picture.h b/cc/debug/traced_picture.h
index 9137d8f..50511f2 100644
--- a/cc/debug/traced_picture.h
+++ b/cc/debug/traced_picture.h
@@ -22,10 +22,17 @@ class TracedPicture : public base::debug::ConvertableToTraceFormat {
   static scoped_ptr<base::debug::ConvertableToTraceFormat>
     AsTraceablePicture(Picture* picture);
 
+  static scoped_ptr<base::debug::ConvertableToTraceFormat>
+    AsTraceablePictureAlias(Picture* original);
+
   virtual void AppendAsTraceFormat(std::string* out) const OVERRIDE;
 
  private:
+  void AppendPicture(std::string* out) const;
+  void AppendPictureAlias(std::string* out) const;
+
   scoped_refptr<Picture> picture_;
+  bool is_alias_;
 
   DISALLOW_COPY_AND_ASSIGN(TracedPicture);
 };
diff --git a/cc/resources/picture.cc b/cc/resources/picture.cc
index 4927623..f9afca9 100644
--- a/cc/resources/picture.cc
+++ b/cc/resources/picture.cc
@@ -199,7 +199,7 @@ void Picture::CloneForDrawing(int num_threads) {
                     pixel_refs_));
     clones_.push_back(clone);
 
-    clone->EmitTraceSnapshot();
+    clone->EmitTraceSnapshotAlias(this);
   }
 }
 
@@ -369,6 +369,14 @@ void Picture::EmitTraceSnapshot() {
       "cc::Picture", this, TracedPicture::AsTraceablePicture(this));
 }
 
+void Picture::EmitTraceSnapshotAlias(Picture* original) {
+  TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(
+      TRACE_DISABLED_BY_DEFAULT("cc.debug"),
+      "cc::Picture",
+      this,
+      TracedPicture::AsTraceablePictureAlias(original));
+}
+
 base::LazyInstance<Picture::PixelRefs>
     Picture::PixelRefIterator::empty_pixel_refs_;
 
diff --git a/cc/resources/picture.h b/cc/resources/picture.h
index 90df190..2386477 100644
--- a/cc/resources/picture.h
+++ b/cc/resources/picture.h
@@ -116,6 +116,7 @@ class CC_EXPORT Picture
   };
 
   void EmitTraceSnapshot();
+  void EmitTraceSnapshotAlias(Picture* original);
 
  private:
   explicit Picture(gfx::Rect layer_rect);