Fixing race conditions in ui::content::WindowSlider which could cause the overscroll overlay to nev…

content/browser/web_contents/aura/overscroll_navigation_overlay.cc

 // Copyright 2014 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/aura/overscroll_navigation_overlay.h"
 
 #include "content/browser/frame_host/navigation_entry_impl.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/browser/web_contents/aura/image_window_delegate.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/common/view_messages.h"
+#include "content/public/browser/render_widget_host_view.h"
 #include "ui/aura/window.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_animation_observer.h"
 #include "ui/compositor/scoped_layer_animation_settings.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/image/image_png_rep.h"
 #include "ui/gfx/image/image_skia.h"
 
 namespace content {
 
@@ skipping 207 matching lines @@
   return CreateSlideLayer(-1);
 }
 
 ui::Layer* OverscrollNavigationOverlay::CreateFrontLayer() {
   if (!web_contents_->GetController().CanGoForward())
     return NULL;
   slide_direction_ = SLIDE_FRONT;
   return CreateSlideLayer(1);
 }
 
-void OverscrollNavigationOverlay::OnWindowSlideComplete() {
-  if (slide_direction_ == SLIDE_UNKNOWN) {
-    window_slider_.reset();
-    StopObservingIfDone();
+void OverscrollNavigationOverlay::OnWindowSlideCompleting() {
+  if (slide_direction_ == SLIDE_UNKNOWN)
     return;
-  }
-
-  // Change the image used for the overlay window.
-  image_delegate_->SetImage(layer_delegate_->image());
-  window_->layer()->SetTransform(gfx::Transform());
-  window_->SchedulePaintInRect(gfx::Rect(window_->bounds().size()));
-
-  SlideDirection direction = slide_direction_;
-  slide_direction_ = SLIDE_UNKNOWN;
 
   // Reset state and wait for the new navigation page to complete
   // loading/painting.
   StartObserving();
 
   // Perform the navigation.
-  if (direction == SLIDE_BACK)
+  if (slide_direction_ == SLIDE_BACK)
     web_contents_->GetController().GoBack();
-  else if (direction == SLIDE_FRONT)
+  else if (slide_direction_ == SLIDE_FRONT)
     web_contents_->GetController().GoForward();
   else
     NOTREACHED();
 
   NavigationEntry* pending_entry =
       web_contents_->GetController().GetPendingEntry();
   // Save id of the pending entry to identify when it loads and paints later.
   // Under some circumstances navigation can leave a null pending entry -
   // see comments in NavigationControllerImpl::NavigateToPendingEntry().
   pending_entry_id_ = pending_entry ? pending_entry->GetUniqueID() : 0;
 }
 
+void OverscrollNavigationOverlay::OnWindowSlideCompleted() {
+  if (slide_direction_ == SLIDE_UNKNOWN) {
+    window_slider_.reset();
+    StopObservingIfDone();
+    return;
+  }
+
+  // Change the image used for the overlay window.
+  image_delegate_->SetImage(layer_delegate_->image());
+  window_->layer()->SetTransform(gfx::Transform());
+  window_->SchedulePaintInRect(gfx::Rect(window_->bounds().size()));
+  slide_direction_ = SLIDE_UNKNOWN;
+
+  // Make sure the overlay layer is repainted before we dismiss it, otherwise
+  // OverlayDismissAnimator may end up showing the wrong screenshot during the
+  // fadeout animation.
+  if (received_paint_update_ && need_paint_update_) {
+    received_paint_update_ = false;
+    RenderWidgetHost* host =
+        web_contents_->GetRenderWidgetHostView()->GetRenderWidgetHost();
+    RenderViewHostImpl* view_host =
+        static_cast<RenderViewHostImpl*> (RenderViewHost::From(host));
+    view_host->ScheduleComposite();
+  } else if (!need_paint_update_) {
+    StopObservingIfDone();
+  }
+}
+
 void OverscrollNavigationOverlay::OnWindowSlideAborted() {
   StopObservingIfDone();
 }
 
 void OverscrollNavigationOverlay::OnWindowSliderDestroyed() {
   // We only want to take an action here if WindowSlider is being destroyed
   // outside of OverscrollNavigationOverlay. If window_slider_.get() is NULL,
   // then OverscrollNavigationOverlay is the one destroying WindowSlider, and
   // we don't need to do anything.
   // This check prevents StopObservingIfDone() being called multiple times
@@ skipping 47 matching lines @@
 bool OverscrollNavigationOverlay::OnMessageReceived(
     const IPC::Message& message) {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   IPC_BEGIN_MESSAGE_MAP(OverscrollNavigationOverlay, message)
     IPC_MESSAGE_HANDLER(ViewHostMsg_UpdateRect, OnUpdateRect)
   IPC_END_MESSAGE_MAP()
   return false;
 }
 
 }  // namespace content