Refactor GestureNavigation to eliminate code redundancy

content/browser/web_contents/aura/overscroll_navigation_overlay.h

Index: content/browser/web_contents/aura/overscroll_navigation_overlay.h
diff --git a/content/browser/web_contents/aura/overscroll_navigation_overlay.h b/content/browser/web_contents/aura/overscroll_navigation_overlay.h
index db9871c024981ff908b20bfd9b2ed1baddcc6eaa..c6f9ada68fb9369f993455a895fd530cb98752ee 100644
--- a/content/browser/web_contents/aura/overscroll_navigation_overlay.h
+++ b/content/browser/web_contents/aura/overscroll_navigation_overlay.h
@@ -7,9 +7,11 @@
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
-#include "content/browser/web_contents/aura/window_slider.h"
+#include "content/browser/web_contents/aura/overscroll_window_animation.h"
+#include "content/browser/web_contents/web_contents_view_aura.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/web_contents_observer.h"
+#include "ui/gfx/image/image.h"
 
 struct ViewHostMsg_UpdateRect_Params;
 
@@ -29,27 +31,15 @@ class OverscrollNavigationOverlayTest;
 // painting.
 class CONTENT_EXPORT OverscrollNavigationOverlay
     : public WebContentsObserver,
-      public WindowSlider::Delegate {
+      public OverscrollWindowAnimation::Delegate {
  public:
-  explicit OverscrollNavigationOverlay(WebContentsImpl* web_contents);
-  ~OverscrollNavigationOverlay() override;
-
-  bool has_window() const { return !!window_.get(); }
+  OverscrollNavigationOverlay(WebContentsImpl* web_contents,
+                              OverscrollWindowAnimation* owa,
+                              aura::Window* web_contents_window);
 
-  // Resets state and starts observing |web_contents_| for page load/paint
-  // updates. This function makes sure that the screenshot window is stacked
-  // on top, so that it hides the content window behind it, and destroys the
-  // screenshot window when the page is done loading/painting.
-  // This should be called immediately after initiating the navigation,
-  // otherwise the overlay may be dismissed prematurely.
-  void StartObserving();
+  ~OverscrollNavigationOverlay() override;
 
-  // Sets the screenshot window and the delegate. This takes ownership of
-  // |window|.
-  // Note that aura_extra::ImageWindowDelegate manages its own lifetime, so this
-  // function does not take ownership of |delegate|.
-  void SetOverlayWindow(scoped_ptr<aura::Window> window,
-                        aura_extra::ImageWindowDelegate* delegate);
+  OverscrollWindowAnimation::Direction direction() { return direction_; }
 
  private:
   friend class OverscrollNavigationOverlayTest;
@@ -64,37 +54,55 @@ class CONTENT_EXPORT OverscrollNavigationOverlay
   FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest,
                            MultiNavigation_PaintUpdate);
 
-  enum SlideDirection {
-    SLIDE_UNKNOWN,
-    SLIDE_BACK,
-    SLIDE_FRONT
-  };
+  // Resets state and starts observing |web_contents_| for page load/paint
+  // updates. This function makes sure that the screenshot window is stacked
+  // on top, so that it hides the content window behind it, and destroys the
+  // screenshot window when the page is done loading/painting.
+  // This should be called immediately after initiating the navigation,
+  // otherwise the overlay may be dismissed prematurely.
+  void StartObserving();
+
+  // Creates the overlay window.
+  void SetupOverlayWindow();
+
+  // Returns the screenshot for the given direction.
+  const gfx::Image GetImageForDirection(
+      OverscrollWindowAnimation::Direction direction) const;
+
+  // Creates the overscroll window if it does not exist or adds a layer if it
+  // does.
+  // TODO find a better name.
+  scoped_ptr<OverscrollLayerWrapper> CreateLayer();
 
   // Stop observing the page and start the final overlay fade-out animation if
   // a window-slide isn't in progress and either the page has been painted or
   // the page-load has completed.
   void StopObservingIfDone();
 
+  // Fades out the overscroll window and dismisses it.
+  void FadeOutOverscrollWindow();
+
   // Creates a layer to be used for window-slide. |offset| is the offset of the
   // NavigationEntry for the screenshot image to display.
   ui::Layer* CreateSlideLayer(int offset);
 
-  // Overridden from WindowSlider::Delegate:
-  ui::Layer* CreateBackLayer() override;
-  ui::Layer* CreateFrontLayer() override;
-  void OnWindowSlideCompleting() override;
-  void OnWindowSlideCompleted(scoped_ptr<ui::Layer> layer) override;
-  void OnWindowSlideAborted() override;
-  void OnWindowSliderDestroyed() override;
+  // Overridden from OverscrollWindowAnimation::Delegate:
+  scoped_ptr<OverscrollLayerWrapper> CreateFrontLayer() override;
+  scoped_ptr<OverscrollLayerWrapper> CreateBackLayer() override;
+  void OnOverscrollCompleted() override;
+  void OnOverscrollCompleting() override;
 
   // Overridden from WebContentsObserver:
   void DidFirstVisuallyNonEmptyPaint() override;
   void DidStopLoading(RenderViewHost* host) override;
 
-  // The WebContents which is being navigated.
+  // The current overscroll direction.
+  OverscrollWindowAnimation::Direction direction_;
+
+  // The web contents that are being navigated.
   WebContentsImpl* web_contents_;
 
-  // The screenshot overlay window.
+  // The window shown on top of the live window for the animations.
   scoped_ptr<aura::Window> window_;
 
   // This is the WindowDelegate of |window_|. The delegate manages its own
@@ -109,20 +117,19 @@ class CONTENT_EXPORT OverscrollNavigationOverlay
   // when the relevant page loads and paints.
   GURL pending_entry_url_;
 
-  // The |WindowSlider| that allows sliding history layers while the page is
-  // being reloaded.
-  scoped_ptr<WindowSlider> window_slider_;
-
   // Layer to be used for the final overlay fadeout animation when the overlay
   // is being dismissed.
   scoped_ptr<ui::Layer> overlay_dismiss_layer_;
 
-  // The direction of the in-progress slide (if any).
-  SlideDirection slide_direction_;
-
   // The LayerDelegate used for the back/front layers during a slide.
   scoped_ptr<ImageLayerDelegate> layer_delegate_;
 
+  // We own the mechanism to animate the windows.
+  OverscrollWindowAnimation* owa_;
+
+  // The window that hosts the web contents.
+  aura::Window* web_contents_window_;
+
   DISALLOW_COPY_AND_ASSIGN(OverscrollNavigationOverlay);
 };