Hack SkRecord in as an alternate recording mode in cc/resources/picture.

cc/resources/picture.cc

Index: cc/resources/picture.cc
diff --git a/cc/resources/picture.cc b/cc/resources/picture.cc
index 8c2ba8aabd233b4a6836ed3590c176ed029a45bd..6ec061bc41f5db03d2c999a02e99a589b3384a39 100644
--- a/cc/resources/picture.cc
+++ b/cc/resources/picture.cc
@@ -191,6 +191,11 @@ Picture::~Picture() {
 }
 
 Picture* Picture::GetCloneForDrawingOnThread(unsigned thread_index) {
+  // We don't need clones to draw from multiple threads with SkRecord.
+  if (playback_.get() != NULL) {

[danakj, 2014/04/22 17:25:53]

nit: if (playback_) is all you need for scoped_ptr

[mtklein, 2014/04/22 17:48:56]

Done everywhere.

+    return this;
+  }
+
   // SkPicture is not thread-safe to rasterize with, this returns a clone
   // to rasterize with on a specific thread.
   CHECK_GE(clones_.size(), thread_index);
@@ -213,6 +218,11 @@ bool Picture::IsSuitableForGpuRasterization() const {
 void Picture::CloneForDrawing(int num_threads) {
   TRACE_EVENT1("cc", "Picture::CloneForDrawing", "num_threads", num_threads);
 
+  // We don't need clones to draw from multiple threads with SkRecord.
+  if (playback_.get() != NULL) {
+    return;
+  }
+
   DCHECK(picture_);
   DCHECK(clones_.empty());
 
@@ -254,6 +264,8 @@ void Picture::Record(ContentLayerClient* painter,
       skia::AdoptRef(new SkTileGridPictureFactory(tile_grid_info));
   SkPictureRecorder recorder(factory.get());
 
+  EXPERIMENTAL::SkRecording* recording = NULL;

[danakj, 2014/04/22 17:25:53]

given the Delete() API I guess this isn't possible, but I really wish this could
be a scoped_ptr. This API requires manual manipulation of this pointer's
lifetime which makes me sad.

[enne (OOO), 2014/04/22 17:26:04]

Can you help me understand the lifetime issues with recordings and canvases? I
assume that the recording holds a ref on the canvas it returns?

It's a little weird to me that you have to explicitly call Delete on a variable
that's only alive for this scope.  Can this not be a scoped_ptr or some similar
Skia construct?

+
   skia::RefPtr<SkCanvas> canvas;
   canvas = skia::SharePtr(
       recorder.beginRecording(layer_rect_.width(),
@@ -272,6 +284,11 @@ void Picture::Record(ContentLayerClient* painter,
       // canvas.
       canvas.clear();
       break;
+    case RECORD_WITH_SKRECORD:
+      recording = EXPERIMENTAL::SkRecording::Create(layer_rect_.width(),
+                                                    layer_rect_.height());
+      canvas = skia::SharePtr(recording->canvas());
+      break;
     default:
       NOTREACHED();
   }
@@ -296,6 +313,11 @@ void Picture::Record(ContentLayerClient* painter,
   picture_ = skia::AdoptRef(recorder.endRecording());
   DCHECK(picture_);
 
+  if (recording != NULL) {

[danakj, 2014/04/22 17:25:53]

nit: just if (recording)

+    canvas.clear();  // Drop ref on canvas before Delete invalidates it.

[enne (OOO), 2014/04/22 17:26:04]

Why?

+    playback_.reset(EXPERIMENTAL::SkRecording::Delete(recording));
+  }
+
   opaque_rect_ = gfx::ToEnclosedRect(opaque_layer_rect);
 
   EmitTraceSnapshot();
@@ -378,7 +400,11 @@ int Picture::Raster(
 
   canvas->scale(contents_scale, contents_scale);
   canvas->translate(layer_rect_.x(), layer_rect_.y());
-  picture_->draw(canvas, callback);
+  if (playback_.get() != NULL) {
+    playback_->draw(canvas);
+  } else {
+    picture_->draw(canvas, callback);
+  }
   SkIRect bounds;
   canvas->getClipDeviceBounds(&bounds);
   canvas->restore();
@@ -393,7 +419,11 @@ void Picture::Replay(SkCanvas* canvas) {
   TRACE_EVENT_BEGIN0("cc", "Picture::Replay");
   DCHECK(picture_);
 
-  picture_->draw(canvas);
+  if (playback_.get() != NULL) {
+    playback_->draw(canvas);
+  } else {
+    picture_->draw(canvas);
+  }
   SkIRect bounds;
   canvas->getClipDeviceBounds(&bounds);
   TRACE_EVENT_END1("cc", "Picture::Replay",