Cleanup: Start using toFoo methods as part of newly adopted coding guideline.

Source/web/tests/ScrollingCoordinatorChromiumTest.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 355 matching lines @@
 
     RenderObject* renderer = scrollableFrame->renderer();
     ASSERT_TRUE(renderer);
     ASSERT_TRUE(renderer->isWidget());
 
     RenderWidget* renderWidget = toRenderWidget(renderer);
     ASSERT_TRUE(renderWidget);
     ASSERT_TRUE(renderWidget->widget());
     ASSERT_TRUE(renderWidget->widget()->isFrameView());
 
-    FrameView* innerFrameView = static_cast<FrameView*>(renderWidget->widget());
+    FrameView* innerFrameView = toFrameView(renderWidget->widget());
     RenderView* innerRenderView = innerFrameView->renderView();
     ASSERT_TRUE(innerRenderView);
 
     RenderLayerCompositor* innerCompositor = innerRenderView->compositor();
     ASSERT_TRUE(innerCompositor->inCompositingMode());
     ASSERT_TRUE(innerCompositor->scrollLayer());
 
     GraphicsLayer* scrollLayer = innerCompositor->scrollLayer();
     ASSERT_EQ(innerFrameView, scrollLayer->scrollableArea());
 
     WebLayer* webScrollLayer = scrollLayer->platformLayer();
     ASSERT_TRUE(webScrollLayer->scrollable());
 
     int expectedScrollPosition = 958 + (innerFrameView->verticalScrollbar()->isOverlayScrollbar() ? 0 : 15);
     ASSERT_EQ(expectedScrollPosition, webScrollLayer->scrollPosition().x);
     ASSERT_EQ(expectedScrollPosition, webScrollLayer->maxScrollPosition().width);
 }
 
 TEST_F(ScrollingCoordinatorChromiumTest, setupScrollbarLayerShouldNotCrash)
 {
     registerMockedHttpURLLoad("setup_scrollbar_layer_crash.html");
     navigateTo(m_baseURL + "setup_scrollbar_layer_crash.html");
     // This test document setup an iframe with scrollbars, then switch to
     // an empty document by javascript.
 }
 
 } // namespace