Make Page Visibility API work when the browser window is visible or not

content/browser/renderer_host/render_widget_host_view_aura.h

 // Copyright (c) 2012 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_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_AURA_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_AURA_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 137 matching lines @@
   void SetBounds(const gfx::Rect& rect) override;
   gfx::Vector2dF GetLastScrollOffset() const override;
   gfx::NativeView GetNativeView() const override;
   gfx::NativeViewId GetNativeViewId() const override;
   gfx::NativeViewAccessible GetNativeViewAccessible() override;
   ui::TextInputClient* GetTextInputClient() override;
   bool HasFocus() const override;
   bool IsSurfaceAvailableForCopy() const override;
   void Show() override;
   void Hide() override;
+  void Hide(bool content_visible) override;
   bool IsShowing() override;
   gfx::Rect GetViewBounds() const override;
   void SetBackgroundColor(SkColor color) override;
   gfx::Size GetVisibleViewportSize() const override;
   void SetInsets(const gfx::Insets& insets) override;
 
   // Overridden from RenderWidgetHostViewBase:
   void InitAsPopup(RenderWidgetHostView* parent_host_view,
                    const gfx::Rect& pos) override;
   void InitAsFullscreen(RenderWidgetHostView* reference_host_view) override;
@@ skipping 482 matching lines @@
   // compositing surface and showing the disambiguation popup.
   gfx::Vector2dF disambiguation_scroll_offset_;
 
   base::WeakPtrFactory<RenderWidgetHostViewAura> weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewAura);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_AURA_H_