Oilpan: move 2D Canvas and WebGL objects to the heap.

Source/core/html/canvas/WebGLRenderbuffer.cpp

Index: Source/core/html/canvas/WebGLRenderbuffer.cpp
diff --git a/Source/core/html/canvas/WebGLRenderbuffer.cpp b/Source/core/html/canvas/WebGLRenderbuffer.cpp
index 76ef482e03748f2fe2614097112908290575c4b6..d45b8df0dfcd804507114452596f0967919bc03e 100644
--- a/Source/core/html/canvas/WebGLRenderbuffer.cpp
+++ b/Source/core/html/canvas/WebGLRenderbuffer.cpp
@@ -31,13 +31,17 @@
 
 namespace WebCore {
 
-PassRefPtr<WebGLRenderbuffer> WebGLRenderbuffer::create(WebGLRenderingContextBase* ctx)
+PassRefPtrWillBeRawPtr<WebGLRenderbuffer> WebGLRenderbuffer::create(WebGLRenderingContextBase* ctx)
 {
-    return adoptRef(new WebGLRenderbuffer(ctx));
+    return adoptRefWillBeNoop(new WebGLRenderbuffer(ctx));
 }
 
 WebGLRenderbuffer::~WebGLRenderbuffer()
 {
+#if ENABLE(OILPAN)
+    m_emulatedStencilBuffer.clear();

[haraken, 2014/07/15 15:04:56]

I'm curious why this is needed.

[sof, 2014/07/15 16:23:00]

m_emulatedStencilBuffer is on the heap. If you look at deleteObjectImpl() below,
it tries to force the deletion of its object, which it cannot do.
m_emulatedStencilBuffer (another WebGLRenderbuffer) clears out its own resource
when finalized.

Promptly deleting the stencil buffer is needed if the object is otherwise
deleted/detached, so removing the call to deleteEmulatedStencilBuffer() entirely
is not on for Oilpan.

+#endif
+    detach();
     deleteObject(0);
 }
 
@@ -66,4 +70,10 @@ void WebGLRenderbuffer::deleteEmulatedStencilBuffer(blink::WebGraphicsContext3D*
     m_emulatedStencilBuffer.clear();
 }
 
+void WebGLRenderbuffer::trace(Visitor* visitor)
+{
+    visitor->trace(m_emulatedStencilBuffer);
+    WebGLSharedObject::trace(visitor);
+}
+
 }