Audited and renamed uses of methods and variables named RootView

Source/core/frame/PinchViewport.h

Index: Source/core/frame/PinchViewport.h
diff --git a/Source/core/frame/PinchViewport.h b/Source/core/frame/PinchViewport.h
index fa5556a1d7315f2c46ede1ddc72d4cae1ebd62d2..451054de9f884fd13799b27ef002b614c8e55f38 100644
--- a/Source/core/frame/PinchViewport.h
+++ b/Source/core/frame/PinchViewport.h
@@ -94,6 +94,9 @@ public:
     void setSize(const IntSize&);
     IntSize size() const { return m_size; }
 
+    // Gets the scaled size, i.e. the viewport in root view space.
+    FloatSize visibleSize() const;
+
     // Resets the viewport to initial state.
     void reset();