Fixes bug in instant that resulted in flickery fade. The problem would

chrome/browser/ui/views/frame/contents_container.cc

Index: chrome/browser/ui/views/frame/contents_container.cc
diff --git a/chrome/browser/ui/views/frame/contents_container.cc b/chrome/browser/ui/views/frame/contents_container.cc
index 0e24ac7a33155707490cea923dbd6f833f86697c..ccf0abd0597b961d9b50ed0d810523adfecb9391 100644
--- a/chrome/browser/ui/views/frame/contents_container.cc
+++ b/chrome/browser/ui/views/frame/contents_container.cc
@@ -5,6 +5,7 @@
 #include "chrome/browser/views/frame/contents_container.h"
 
 #include "app/slide_animation.h"
+#include "base/logging.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "views/background.h"
 #include "views/widget/root_view.h"
@@ -14,11 +15,35 @@
 static const int kMinOpacity = 0;
 static const int kMaxOpacity = 192;
 
+// View used to track when the overlay widget is destroyed. If the
+// ContentsContainer is still valid when the destructor is invoked this invokes
+// |OverlayViewDestroyed| on the ContentsContainer.
+class ContentsContainer::OverlayContentView : public views::View {
+ public:
+  explicit OverlayContentView(ContentsContainer* container)
+      : container_(container) {
+  }
+  ~OverlayContentView() {
+    if (container_)
+      container_->OverlayViewDestroyed();
+  }
+
+  void Detach() {
+    container_ = NULL;
+  }
+
+ private:
+  ContentsContainer* container_;
+
+  DISALLOW_COPY_AND_ASSIGN(OverlayContentView);
+};
+
 ContentsContainer::ContentsContainer(views::View* active)
     : active_(active),
       preview_(NULL),
       preview_tab_contents_(NULL),
       active_overlay_(NULL),
+      overlay_view_(NULL),
       active_top_margin_(0) {
   AddChildView(active_);
 }
@@ -26,6 +51,8 @@ ContentsContainer::ContentsContainer(views::View* active)
 ContentsContainer::~ContentsContainer() {
   // We don't need to explicitly delete active_overlay_ as it'll be deleted by
   // virtue of being a child window.
+  if (overlay_view_)
+    overlay_view_->Detach();
 }
 
 void ContentsContainer::MakePreviewContentsActiveContents() {
@@ -82,26 +109,21 @@ void ContentsContainer::FadeActiveContents() {
   overlay_animation_->SetSlideDuration(300);
   overlay_animation_->Show();
 
-  active_overlay_ = views::Widget::CreatePopupWidget(views::Widget::Transparent,
-                                              views::Widget::NotAcceptEvents,
-                                              views::Widget::DeleteOnDestroy,
-                                              views::Widget::MirrorOriginInRTL);
-  active_overlay_->SetOpacity(0);
-  gfx::Point screen_origin;
-  views::View::ConvertPointToScreen(active_, &screen_origin);
-  gfx::Rect overlay_bounds(screen_origin, active_->size());
-  active_overlay_->Init(active_->GetWidget()->GetNativeView(), overlay_bounds);
-  views::View* content_view = new views::View();
-  content_view->set_background(
-      views::Background::CreateSolidBackground(SK_ColorWHITE));
-  active_overlay_->SetContentsView(content_view);
-  active_overlay_->Show();
-  active_overlay_->MoveAbove(active_->GetWidget());
+  CreateOverlay(kMinOpacity);
+}
+
+void ContentsContainer::ShowFade() {
+  if (active_overlay_ || !Animation::ShouldRenderRichAnimation())
+    return;
+
+  CreateOverlay(kMaxOpacity);
 }
 
 void ContentsContainer::RemoveFade() {
   overlay_animation_.reset();
   if (active_overlay_) {
+    overlay_view_->Detach();
+    overlay_view_ = NULL;
     active_overlay_->Close();
     active_overlay_ = NULL;
   }
@@ -126,3 +148,27 @@ void ContentsContainer::Layout() {
   // still need a layout.
   views::View::Layout();
 }
+
+void ContentsContainer::CreateOverlay(int initial_opacity) {
+  DCHECK(!active_overlay_);
+  active_overlay_ = views::Widget::CreatePopupWidget(views::Widget::Transparent,
+                                              views::Widget::NotAcceptEvents,
+                                              views::Widget::DeleteOnDestroy,
+                                              views::Widget::MirrorOriginInRTL);
+  active_overlay_->SetOpacity(initial_opacity);
+  gfx::Point screen_origin;
+  views::View::ConvertPointToScreen(active_, &screen_origin);
+  gfx::Rect overlay_bounds(screen_origin, active_->size());
+  active_overlay_->Init(active_->GetWidget()->GetNativeView(), overlay_bounds);
+  overlay_view_ = new OverlayContentView(this);
+  overlay_view_->set_background(
+      views::Background::CreateSolidBackground(SK_ColorWHITE));
+  active_overlay_->SetContentsView(overlay_view_);
+  active_overlay_->Show();
+  active_overlay_->MoveAbove(active_->GetWidget());
+}
+
+void ContentsContainer::OverlayViewDestroyed() {
+  active_overlay_ = NULL;
+  overlay_view_ = NULL;
+}