Aura: Have ui::Layer implement WebKit::WebExternalTextureLayerClient

ui/compositor/compositor.cc

Index: ui/compositor/compositor.cc
diff --git a/ui/compositor/compositor.cc b/ui/compositor/compositor.cc
index 148a5bd28c782ebc0a5ebac6fa65742d4d092717..d1938f5879cd9950e5fdf3f50b6b0aab7a512a39 100644
--- a/ui/compositor/compositor.cc
+++ b/ui/compositor/compositor.cc
@@ -162,6 +162,9 @@ Compositor::Compositor(CompositorDelegate* delegate,
 }
 
 Compositor::~Compositor() {
+  // Clear out any pending callbacks.
+  didCommit();
+
   // Don't call |CompositorDelegate::ScheduleDraw| from this point.
   delegate_ = NULL;
   // There's a cycle between |root_web_layer_| and |host_|, which results in
@@ -170,6 +173,11 @@ Compositor::~Compositor() {
   host_.setRootLayer(NULL);
   if (root_layer_)
     root_layer_->SetCompositor(NULL);
+
+  // Stop all outstanding draws before telling the ContextFactory to tear
+  // down any contexts that the host_ may rely upon.
+  host_.reset();
+
   if (!test_compositor_enabled)
     ContextFactory::GetInstance()->RemoveCompositor(this);
 }
@@ -342,6 +350,17 @@ WebKit::WebGraphicsContext3D* Compositor::createContext3D() {
 void Compositor::didRebindGraphicsContext(bool success) {
 }
 
+// Called once per draw in single-threaded compositor mode and potentially
+// many times between draws in the multi-threaded compositor mode.
+void Compositor::didCommit() {
+  for (std::vector< base::Callback<void(Compositor*)> >::const_iterator
+      it = did_commit_callbacks_.begin();
+      it != did_commit_callbacks_.end(); ++it) {
+    it->Run(this);

[piman, 2012/07/12 00:18:09]

btw, you run the risk of the closure modifying did_commit_callbacks_.
FWIW FOR_EACH_OBSERVER deals with this correctly.

+  }
+  did_commit_callbacks_.clear();
+}
+
 void Compositor::didCommitAndDrawFrame() {
   // TODO(backer): Plumb through an earlier impl side will start.
   if (g_compositor_thread)
@@ -363,6 +382,11 @@ void Compositor::scheduleComposite() {
     ScheduleDraw();
 }
 
+void Compositor::AddDidCommitCallback(
+    const base::Callback<void(ui::Compositor*)>& callback) {
+  did_commit_callbacks_.push_back(callback);
+}
+
 void Compositor::SwizzleRGBAToBGRAAndFlip(unsigned char* pixels,
                                           const gfx::Size& image_size) {
   // Swizzle from RGBA to BGRA