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 20d15335b4b2fe76d046435e8db87975ac549b35..a406c1e4ef9221d454fc6a4545bf7a20a286f58c 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();