Enable video painting on Canvas for Chrome on Android.

Source/WebCore/html/HTMLVideoElement.cpp

Index: Source/WebCore/html/HTMLVideoElement.cpp
diff --git a/Source/WebCore/html/HTMLVideoElement.cpp b/Source/WebCore/html/HTMLVideoElement.cpp
index 02ec2c41fc2c6e32e470d811693d68bc2ac75e60..5fd1a0f4ab6bf6f46a50baaf6f70a11ef8d20d44 100644
--- a/Source/WebCore/html/HTMLVideoElement.cpp
+++ b/Source/WebCore/html/HTMLVideoElement.cpp
@@ -34,6 +34,7 @@
 #include "Document.h"
 #include "ExceptionCode.h"
 #include "Frame.h"
+#include "GraphicsContext3D.h"
 #include "HTMLImageLoader.h"
 #include "HTMLNames.h"
 #include "HTMLParserIdioms.h"
@@ -42,6 +43,7 @@
 #include "RenderVideo.h"
 #include "ScriptController.h"
 #include "Settings.h"
+#include "SharedGraphicsContext3D.h"
 
 namespace WebCore {
 
@@ -241,6 +243,14 @@ void HTMLVideoElement::paintCurrentFrameInContext(GraphicsContext* context, cons
         return;
     
     player->setVisible(true); // Make player visible or it won't draw.
+
+    // Go through the fast path trying to do a GPU-GPU texture copy without a readback to system memory if possible.
+    // Otherwise, it will fallback to the normal SW path.
+    RefPtr<GraphicsContext3D> context3D = SharedGraphicsContext3D::get();
+    if (context3D && player->copyVideoTextureToCanvas(context, context3D.get()))

[scherkus (not reviewing), 2013/04/05 20:47:09]

this seems strange

there are other callers of paintCurrentFrameInContext() besides canvas

what happens in the cases where this is called but we're not painting into a
canvas?

[Ken Russell (switch to Gerrit), 2013/04/05 22:40:38]

I'll be more blunt and say that there is no way this can be doing the right
thing, because it is ignoring the destRect argument.

[hkuang, 2013/04/09 17:46:10]

Done.

[hkuang, 2013/04/09 17:46:10]

Fix the naming issue when addressing Ken's comments. Actually the backend of the
GraphicsContext is the SkCanvas.

+        return;
+
+    // Normal pure SW path
     player->paintCurrentFrameInContext(context, destRect);
 }