Made root translation layer the root when using pinch virtual viewport.

Source/web/tests/PinchViewportTest.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 
 #include "core/frame/PinchViewport.h"
 
 #include "core/frame/FrameHost.h"
 #include "core/frame/LocalFrame.h"
@@ skipping 198 matching lines @@
 {
     initializeWithDesktopSettings(turnOffForceCompositingMode);
     webViewImpl()->resize(IntSize(320, 240));
 
     navigateTo("about:blank");
     forceFullCompositingUpdate();
     webViewImpl()->settings()->setAcceleratedCompositingEnabled(true);
     webViewImpl()->layout();
 
     PinchViewport& pinchViewport = frame()->page()->frameHost().pinchViewport();
-    EXPECT_FLOAT_SIZE_EQ(FloatSize(320, 240), pinchViewport.rootGraphicsLayer()->size());
+    EXPECT_FLOAT_SIZE_EQ(FloatSize(320, 240), pinchViewport.containerLayer()->size());
 }
 // Make sure that the visibleRect method acurately reflects the scale and scroll location
 // of the viewport.
 TEST_F(PinchViewportTest, TestVisibleRect)
 {
     initializeWithDesktopSettings();
     webViewImpl()->resize(IntSize(320, 240));
 
     navigateTo("about:blank");
     forceFullCompositingUpdate();
@@ skipping 530 matching lines @@
     pinchViewport.scrollIntoView(FloatRect(50, 75, 50, 75));
     EXPECT_POINT_EQ(IntPoint(50, 75), frame()->view()->scrollPosition());
     EXPECT_FLOAT_POINT_EQ(FloatPoint(), pinchViewport.visibleRect().location());
 
     pinchViewport.scrollIntoView(FloatRect(190, 290, 10, 10));
     EXPECT_POINT_EQ(IntPoint(100, 150), frame()->view()->scrollPosition());
     EXPECT_FLOAT_POINT_EQ(FloatPoint(50, 75), pinchViewport.visibleRect().location());
 }
 
 } // namespace