Very basic Android browser-side compositing support.

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index ecd1f40ce0c36f9d6fc8155f7afeee9f5d4f1988..3ecbf5e5a89ecd6aa2746b6b3a584c7251b86cd2 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -1369,6 +1369,16 @@ void WebContentsImpl::RequestMediaAccessPermission(
     callback.Run(content::MediaStreamDevices());
 }
 
+void WebContentsImpl::AttachLayer(WebKit::WebLayer& layer) {
+  if (delegate_)
+    delegate_->AttachLayer(this, layer);

[klobag.chromium, 2012/08/22 07:01:19]

Isn't this assume WebContentsImpl only have one WebLayer?

WebContentsImpl uses RenderViewHostManager to manage the RenderWidgetHost. We
need to be careful of this.

[no sievers, 2012/08/22 21:17:40]

It could end up adding more than one theoretically, but since I set
drawsContent() to true/false in RWHVA::Show()/Hide(), only one should render at
any given time.

+}
+
+void WebContentsImpl::RemoveLayer(WebKit::WebLayer& layer) {
+  if (delegate_)
+    delegate_->RemoveLayer(this, layer);
+}
+
 void WebContentsImpl::UpdatePreferredSize(const gfx::Size& pref_size) {
   preferred_size_ = pref_size;
   if (delegate_)