Oilpan: Remove guardRef and guardDeref from TreeScope.

Source/core/html/canvas/WebGLRenderingContext.cpp

Index: Source/core/html/canvas/WebGLRenderingContext.cpp
diff --git a/Source/core/html/canvas/WebGLRenderingContext.cpp b/Source/core/html/canvas/WebGLRenderingContext.cpp
index 598948f3239f328da687fb7d1c38daab43c1b63f..fec881c51657e4e8b3d45a2c00414439a35a9697 100644
--- a/Source/core/html/canvas/WebGLRenderingContext.cpp
+++ b/Source/core/html/canvas/WebGLRenderingContext.cpp
@@ -60,7 +60,7 @@
 
 namespace WebCore {
 
-PassOwnPtr<WebGLRenderingContext> WebGLRenderingContext::create(HTMLCanvasElement* canvas, WebGLContextAttributes* attrs)
+PassOwnPtrWillBeRawPtr<WebGLRenderingContext> WebGLRenderingContext::create(HTMLCanvasElement* canvas, WebGLContextAttributes* attrs)
 {
     Document& document = canvas->document();
     LocalFrame* frame = document.frame();
@@ -94,7 +94,7 @@ PassOwnPtr<WebGLRenderingContext> WebGLRenderingContext::create(HTMLCanvasElemen
     if (extensionsUtil.supportsExtension("GL_EXT_debug_marker"))
         context->pushGroupMarkerEXT("WebGLRenderingContext");
 
-    OwnPtr<WebGLRenderingContext> renderingContext = adoptPtr(new WebGLRenderingContext(canvas, context.release(), attrs));
+    OwnPtrWillBeRawPtr<WebGLRenderingContext> renderingContext = adoptPtrWillBeNoop(new WebGLRenderingContext(canvas, context.release(), attrs));
     renderingContext->registerContextExtensions();
     renderingContext->suspendIfNeeded();