Fix visual viewport for OOPIF.

content/browser/frame_host/render_widget_host_view_child_frame.h

 // 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.
 
 #ifndef CONTENT_BROWSER_FRAME_HOST_RENDER_WIDGET_HOST_VIEW_CHILD_FRAME_H_
 #define CONTENT_BROWSER_FRAME_HOST_RENDER_WIDGET_HOST_VIEW_CHILD_FRAME_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 65 matching lines @@
   RenderWidgetHost* GetRenderWidgetHost() const override;
   void SetSize(const gfx::Size& size) override;
   void SetBounds(const gfx::Rect& rect) override;
   void Focus() override;
   bool HasFocus() const override;
   bool IsSurfaceAvailableForCopy() const override;
   void Show() override;
   void Hide() override;
   bool IsShowing() override;
   gfx::Rect GetViewBounds() const override;
+  gfx::Size GetVisibleViewportSize() const override;
   gfx::Vector2dF GetLastScrollOffset() const override;
   gfx::NativeView GetNativeView() const override;
   gfx::NativeViewId GetNativeViewId() const override;
   gfx::NativeViewAccessible GetNativeViewAccessible() override;
   void SetBackgroundColor(SkColor color) override;
   gfx::Size GetPhysicalBackingSize() const override;
 
   // RenderWidgetHostViewBase implementation.
   void InitAsPopup(RenderWidgetHostView* parent_host_view,
                    const gfx::Rect& bounds) override;
@@ skipping 137 matching lines @@
   // it convenient to swap() when processing the list.
   FrameSwappedCallbackList frame_swapped_callbacks_;
 
   base::WeakPtrFactory<RenderWidgetHostViewChildFrame> weak_factory_;
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewChildFrame);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_RENDER_WIDGET_HOST_VIEW_CHILD_FRAME_H_