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

Source/core/html/canvas/WebGLObject.cpp

Index: Source/core/html/canvas/WebGLObject.cpp
diff --git a/Source/core/html/canvas/WebGLObject.cpp b/Source/core/html/canvas/WebGLObject.cpp
index bcc8adc3e9dcf171d5ec2b735ef97a69bf0ea79a..802a4ad3ff189e641eca85554c0fd8bb0c1cf36c 100644
--- a/Source/core/html/canvas/WebGLObject.cpp
+++ b/Source/core/html/canvas/WebGLObject.cpp
@@ -38,6 +38,8 @@ WebGLObject::WebGLObject(WebGLRenderingContextBase*)
 
 WebGLObject::~WebGLObject()
 {
+    // Verify that platform objects have been explicitly deleted.
+    ASSERT(m_deleted);
 }
 
 void WebGLObject::setObject(Platform3DObject object)
@@ -70,8 +72,25 @@ void WebGLObject::deleteObject(blink::WebGraphicsContext3D* context3d)
 void WebGLObject::detach()
 {
     m_attachmentCount = 0; // Make sure OpenGL resource is deleted.
-    }
+}
 
+void WebGLObject::detachAndDeleteObject()
+{
+    // Helper method that pairs detachment with platform object
+    // deletion.
+    //
+    // With Oilpan enabled, objects may end up being finalized without
+    // having been detached first. Consequently, the objects force
+    // detachment first before deleting the platform object. Without
+    // Oilpan, the objects will have been detached from the 'parent'
+    // objects first and do not separately require it when finalizing.
+    //
+    // However, as detach() is trivial, the individual WebGL
+    // destructors will always call detachAndDeleteObject() rather
+    // than do it based on Oilpan being enabled.
+    detach();
+    deleteObject(0);
+}
 
 void WebGLObject::onDetached(blink::WebGraphicsContext3D* context3d)
 {