overscroll: Show the screenshot of the navigation-entry when doing overscroll.

content/browser/web_contents/web_contents_view_aura.cc

 // 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.
 
 #include "content/browser/web_contents/web_contents_view_aura.h"
 
 #include "base/auto_reset.h"
 #include "base/utf_string_conversions.h"
 #include "content/browser/renderer_host/dip_util.h"
 #include "content/browser/renderer_host/overscroll_controller.h"
 #include "content/browser/renderer_host/render_view_host_factory.h"
 #include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/browser/renderer_host/render_widget_host_view_aura.h"
 #include "content/browser/web_contents/interstitial_page_impl.h"
+#include "content/browser/web_contents/navigation_entry_impl.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/notification_source.h"
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/overscroll_configuration.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/render_widget_host.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/browser/web_contents_view_delegate.h"
 #include "content/public/browser/web_drag_dest_delegate.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebInputEvent.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/client/drag_drop_client.h"
 #include "ui/aura/client/drag_drop_delegate.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/root_window_observer.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_observer.h"
 #include "ui/base/clipboard/custom_data_helper.h"
 #include "ui/base/dragdrop/drag_drop_types.h"
 #include "ui/base/dragdrop/drag_utils.h"
 #include "ui/base/dragdrop/os_exchange_data.h"
 #include "ui/base/events/event.h"
 #include "ui/base/events/event_utils.h"
 #include "ui/base/hit_test.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/scoped_layer_animation_settings.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/image/image.h"
+#include "ui/gfx/image/image_png_rep.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/screen.h"
 #include "webkit/glue/webdropdata.h"
 
 #if defined(OS_WIN)
 #include "ui/base/clipboard/clipboard_util_win.h"
 #endif
 
 namespace content {
 WebContentsView* CreateWebContentsView(
     WebContentsImpl* web_contents,
     WebContentsViewDelegate* delegate,
     RenderViewHostDelegateView** render_view_host_delegate_view) {
   WebContentsViewAura* rv = new WebContentsViewAura(web_contents, delegate);
   *render_view_host_delegate_view = rv;
   return rv;
 }
 
 namespace {
 
 // The window delegate for the overscroll window. This redirects trackpad events
 // to the web-contents window. The delegate destroys itself when the window is
 // destroyed.
 class OverscrollWindowDelegate : public aura::WindowDelegate {
  public:
-  explicit OverscrollWindowDelegate(aura::Window* web_contents_window)
-      : web_contents_window_(web_contents_window) {
+  OverscrollWindowDelegate(WebContentsImpl* web_contents,
+                           OverscrollMode overscroll_mode)
+      : web_contents_window_(web_contents->GetView()->GetContentNativeView()) {
+    const NavigationControllerImpl& controller = web_contents->GetController();
+    const NavigationEntryImpl* entry = NULL;
+    if (overscroll_mode == OVERSCROLL_WEST && controller.CanGoForward()) {
+      entry = NavigationEntryImpl::FromNavigationEntry(
+          controller.GetEntryAtOffset(1));
+    } else if (overscroll_mode == OVERSCROLL_EAST && controller.CanGoBack()) {
+      entry = NavigationEntryImpl::FromNavigationEntry(
+          controller.GetEntryAtOffset(-1));
+    }
+    if (!entry || !entry->screenshot())
+      return;
+
+    std::vector<gfx::ImagePNGRep> image_reps;
+    image_reps.push_back(gfx::ImagePNGRep(entry->screenshot(),
+          ui::GetScaleFactorForNativeView(web_contents_window_)));
+    image_ = gfx::Image(image_reps);
   }
 
  private:
   virtual ~OverscrollWindowDelegate() {}
 
   // aura::WindowDelegate implementation:
   virtual gfx::Size GetMinimumSize() const OVERRIDE {
     return gfx::Size();
   }
 
@@ skipping 20 matching lines @@
   }
 
   virtual bool CanFocus() OVERRIDE {
     return false;
   }
 
   virtual void OnCaptureLost() OVERRIDE {
   }
 
   virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE {
+    if (image_.IsEmpty())
+      canvas->DrawColor(SK_ColorGRAY);
+    else
+      canvas->DrawImageInt(image_.AsImageSkia(), 0, 0);
   }
 
   virtual void OnDeviceScaleFactorChanged(float device_scale_factor) OVERRIDE {
   }
 
   virtual void OnWindowDestroying() OVERRIDE {
   }
 
   virtual void OnWindowDestroyed() OVERRIDE {
     delete this;
@@ skipping 12 matching lines @@
   virtual scoped_refptr<ui::Texture> CopyTexture() OVERRIDE {
     return scoped_refptr<ui::Texture>();
   }
 
   // Overridden from ui::EventHandler.
   virtual void OnScrollEvent(ui::ScrollEvent* event) OVERRIDE {
     web_contents_window_->delegate()->OnScrollEvent(event);
   }
 
   aura::Window* web_contents_window_;
+  gfx::Image image_;
 
   DISALLOW_COPY_AND_ASSIGN(OverscrollWindowDelegate);
 };
 
 // Listens to all mouse drag events during a drag and drop and sends them to
 // the renderer.
 class WebDragSourceAura : public MessageLoopForUI::Observer,
                           public NotificationObserver {
  public:
   WebDragSourceAura(aura::Window* window, WebContentsImpl* contents)
@@ skipping 322 matching lines @@
   // completed immidiately, which triggers |OnImplicitAnimationsCompleted()|
   // callback, and that tries to reset |overscroll_window_| again, causing a
   // double-free. So use a temporary variable here.
   if (overscroll_window_.get()) {
     base::AutoReset<OverscrollMode> reset_state(&current_overscroll_gesture_,
                                                 current_overscroll_gesture_);
     scoped_ptr<aura::Window> reset_window(overscroll_window_.release());
   }
 
   overscroll_window_.reset(new aura::Window(new OverscrollWindowDelegate(
-      GetContentNativeView())));
+      web_contents_,
+      current_overscroll_gesture_)));
   overscroll_window_->SetType(aura::client::WINDOW_TYPE_CONTROL);
   overscroll_window_->SetTransparent(false);
-  overscroll_window_->Init(ui::LAYER_SOLID_COLOR);
+  overscroll_window_->Init(ui::LAYER_TEXTURED);
   overscroll_window_->layer()->SetMasksToBounds(true);
-  overscroll_window_->layer()->SetColor(SK_ColorGRAY);
   overscroll_window_->SetName("OverscrollOverlay");
 
   window_->AddChild(overscroll_window_.get());
 
   gfx::Rect bounds = gfx::Rect(window_->bounds().size());
   if (current_overscroll_gesture_ == OVERSCROLL_WEST &&
       web_contents_->GetController().CanGoForward()) {
     // The overlay will be sliding in from the right edge towards the left.
     // So position the overlay window on the right of the window.
     bounds.Offset(bounds.width(), 0);
@@ skipping 578 matching lines @@
       event.location(),
       gfx::Screen::GetScreenFor(GetNativeView())->GetCursorScreenPoint(),
       ConvertAuraEventFlagsToWebInputEventModifiers(event.flags()));
   if (drag_dest_delegate_)
     drag_dest_delegate_->OnDrop();
   current_drop_data_.reset();
   return current_drag_op_;
 }
 
 }  // namespace content