content/browser/web_contents/aura/overscroll_navigation_overlay.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_BROWSER_WEB_CONTENTS_AURA_OVERSCROLL_NAVIGATION_OVERLAY_H_
   6 #define CONTENT_BROWSER_WEB_CONTENTS_AURA_OVERSCROLL_NAVIGATION_OVERLAY_H_
   7
   8 #include "base/gtest_prod_util.h"
   9 #include "base/macros.h"
  10 #include "content/browser/web_contents/aura/overscroll_window_animation.h"
  11 #include "content/browser/web_contents/web_contents_view_aura.h"
  12 #include "content/common/content_export.h"
  13 #include "content/public/browser/web_contents_observer.h"
  14 #include "ui/gfx/image/image.h"
  15
  16 struct ViewHostMsg_UpdateRect_Params;
  17
  18 namespace content {
  19
  20 class OverscrollWindowDelegate;
  21 class OverscrollNavigationOverlayTest;
  22 class ScopedLayerClippingSetting;
  23
  24 // When a history navigation is triggered at the end of an overscroll
  25 // navigation, it is necessary to show the history-screenshot until the page is
  26 // done navigating and painting. This class accomplishes this by calling the
  27 // navigation and creating, showing and destroying the screenshot window on top
  28 // of the page until the page has completed loading and painting. When the
  29 // overscroll completes, this screenshot window is returned by
  30 // OnOverscrollComplete and |window_| is set to own it.
  31 // There are two overscroll cases, for the first one the main window is the web
  32 // contents window. At this stage, |window_| is null. The second case is
  33 // triggered if the user overscrolls after |window_| is set, before the page
  34 // finishes loading. When this happens, |window_| is the main window.
  35 class CONTENT_EXPORT OverscrollNavigationOverlay
  36     : public WebContentsObserver,
  37       public OverscrollWindowAnimation::Delegate {
  38  public:
  39   // Note that this enum is used to back an UMA histogram, so it should be
  40   // treated as append-only.
  41   enum NavigationDirection { NONE, FORWARD, BACK, NAVIGATION_COUNT };
  42
  43   OverscrollNavigationOverlay(WebContentsImpl* web_contents,
  44                               aura::Window* web_contents_window);
  45
  46   ~OverscrollNavigationOverlay() override;
  47
  48   // Returns a pointer to the relay delegate we own.
  49   OverscrollControllerDelegate* relay_delegate() { return owa_.get(); }
  50
  51  private:
  52   class ScopedLayerClippingSetting;
  53
  54   friend class OverscrollNavigationOverlayTest;
  55   FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest, WithScreenshot);
  56   FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest, WithoutScreenshot);
  57   FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest, CannotNavigate);
  58   FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest, CancelNavigation);
  59   FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest,
  60                            CancelAfterSuccessfulNavigation);
  61   FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest, OverlayWindowSwap);
  62
  63   // Resets state and starts observing |web_contents_| for page load/paint
  64   // updates. This function makes sure that the screenshot window is stacked
  65   // on top, so that it hides the content window behind it, and destroys the
  66   // screenshot window when the page is done loading/painting.
  67   // This should be called immediately after initiating the navigation,
  68   // otherwise the overlay may be dismissed prematurely.
  69   void StartObserving();
  70
  71   // Stop observing the page and start the final overlay fade-out animation if
  72   // there's no active overscroll window animation.
  73   void StopObservingIfDone();
  74
  75   // Creates a window that shows a history-screenshot and is stacked relative to
  76   // the current overscroll |direction_| with the given |bounds|.
  77   scoped_ptr<aura::Window> CreateOverlayWindow(const gfx::Rect& bounds);
  78
  79   // Returns an image with the history-screenshot for the previous or next page,
  80   // according to the given |direction|.
  81   const gfx::Image GetImageForDirection(NavigationDirection direction) const;
  82
  83   // Overridden from OverscrollWindowAnimation::Delegate:
  84   scoped_ptr<aura::Window> CreateFrontWindow(const gfx::Rect& bounds) override;
  85   scoped_ptr<aura::Window> CreateBackWindow(const gfx::Rect& bounds) override;
  86   aura::Window* GetMainWindow() const override;
  87   void OnOverscrollCompleting() override;
  88   void OnOverscrollCompleted(scoped_ptr<aura::Window> window) override;
  89   void OnOverscrollCancelled() override;
  90
  91   // Overridden from WebContentsObserver:
  92   void DidFirstVisuallyNonEmptyPaint() override;
  93   void DidStopLoading() override;
  94
  95   // The current overscroll direction.
  96   NavigationDirection direction_;
  97
  98   // The web contents that are being navigated.
  99   WebContentsImpl* web_contents_;
 100
 101   // The overlay window that shows a screenshot during an overscroll gesture and
 102   // handles overscroll events during the second overscroll case.
 103   scoped_ptr<aura::Window> window_;
 104
 105   bool loading_complete_;
 106   bool received_paint_update_;
 107
 108   // URL of the NavigationEntry we are navigating to. This is needed to
 109   // filter on WebContentsObserver callbacks and is used to dismiss the overlay
 110   // when the relevant page loads and paints.
 111   GURL pending_entry_url_;
 112
 113   // Manages the overscroll animations.
 114   scoped_ptr<OverscrollWindowAnimation> owa_;
 115
 116   // The window that hosts the web contents.
 117   aura::Window* web_contents_window_;
 118
 119   // Scoped clipping settings for the contents layer and its parent.
 120   scoped_ptr<ScopedLayerClippingSetting> contents_layer_settings_;
 121   scoped_ptr<ScopedLayerClippingSetting> contents_layer_parent_settings_;
 122
 123   DISALLOW_COPY_AND_ASSIGN(OverscrollNavigationOverlay);
 124 };
 125
 126 }  // namespace content
 127
 128 #endif  // CONTENT_BROWSER_WEB_CONTENTS_AURA_OVERSCROLL_NAVIGATION_OVERLAY_H_