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