Ensure that the focus ring in the bookmarks bar does not paint outside the parent view.

ui/views/controls/scroll_view.h

 // 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.
 
 #ifndef UI_VIEWS_CONTROLS_SCROLL_VIEW_H_
 #define UI_VIEWS_CONTROLS_SCROLL_VIEW_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "ui/views/controls/scrollbar/scroll_bar.h"
 
 namespace gfx {
 class ScrollOffset;
 }
 
 namespace views {
+class ViewObserverTest;
+
 namespace test {
 class ScrollViewTestApi;
 }
 
 /////////////////////////////////////////////////////////////////////////////
 //
 // ScrollView class
 //
 // A ScrollView is used to make any View scrollable. The view is added to
 // a viewport which takes care of clipping.
@@ skipping 68 matching lines @@
   // View overrides:
   gfx::Size GetPreferredSize() const override;
   int GetHeightForWidth(int width) const override;
   void Layout() override;
   bool OnKeyPressed(const ui::KeyEvent& event) override;
   bool OnMouseWheel(const ui::MouseWheelEvent& e) override;
   void OnScrollEvent(ui::ScrollEvent* event) override;
   void OnGestureEvent(ui::GestureEvent* event) override;
   const char* GetClassName() const override;
   void OnNativeThemeChanged(const ui::NativeTheme* theme) override;
+  void ViewHierarchyChanged(
+      const ViewHierarchyChangedDetails& details) override;
+  void OnChildLayerChanged(View* child) override;
 
   // ScrollBarController overrides:
   void ScrollToPosition(ScrollBar* source, int position) override;
   int GetScrollIncrement(ScrollBar* source,
                          bool is_page,
                          bool is_positive) override;
 
   // TODO(djacobo): Remove this method when http://crbug.com/656198  is closed.
   // Force |contents_viewport_| to enable a Layer().
   void EnableViewPortLayer();
 
  private:
   friend class test::ScrollViewTestApi;
+  FRIEND_TEST_ALL_PREFIXES(ViewObserverTest, ScrollViewChildAddLayerTest);
 
   class Viewport;
 
   // Used internally by SetHeader() and SetContents() to reset the view.  Sets
   // |member| to |new_view|. If |new_view| is non-null it is added to |parent|.
   void SetHeaderOrContents(View* parent, View* new_view, View** member);
 
   // Scrolls the minimum amount necessary to make the specified rectangle
   // visible, in the coordinates of the contents view. The specified rectangle
   // is constrained by the bounds of the contents view. This has no effect if
@@ skipping 24 matching lines @@
 
   // Callback entrypoint when hosted Layers are scrolled by the Compositor.
   void OnLayerScrolled(const gfx::ScrollOffset& offset);
 
   // Horizontally scrolls the header (if any) to match the contents.
   void ScrollHeader();
 
   void AddBorder();
   void UpdateBorder();
 
+  // Enables view port layering if |child| or any of its descendants has a
+  // layer. Returns true if yes. We short circuit the recursion if we enabled
+  // layering.
+  bool EnableLayeringRecursivelyForChild(View* child);
+
   // The current contents and its viewport. |contents_| is contained in
   // |contents_viewport_|.
   View* contents_;
   View* contents_viewport_;
 
   // The current header and its viewport. |header_| is contained in
   // |header_viewport_|.
   View* header_;
   View* header_viewport_;
 
@@ skipping 22 matching lines @@
   // In Harmony, the indicator is a focus ring. Pre-Harmony, the indicator is a
   // different border painter.
   bool draw_focus_indicator_ = false;
 
   // Only needed for pre-Harmony. Remove when Harmony is default.
   bool draw_border_ = false;
 
   // Focus ring, if one is installed.
   View* focus_ring_ = nullptr;
 
+  // Set to true if we enabled layering for the viewport.
+  bool viewport_layer_enabled_ = false;
+
+  // Set to true if the scroll with layers feature is enabled.
+  const bool scroll_with_layers_enabled_;
+
   DISALLOW_COPY_AND_ASSIGN(ScrollView);
 };
 
 // VariableRowHeightScrollHelper is intended for views that contain rows of
 // varying height. To use a VariableRowHeightScrollHelper create one supplying
 // a Controller and delegate GetPageScrollIncrement and GetLineScrollIncrement
 // to the helper. VariableRowHeightScrollHelper calls back to the
 // Controller to determine row boundaries.
 class VariableRowHeightScrollHelper {
  public:
@@ skipping 56 matching lines @@
  private:
   int top_margin_;
   int row_height_;
 
   DISALLOW_COPY_AND_ASSIGN(FixedRowHeightScrollHelper);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_SCROLL_VIEW_H_