Updated DropdownBarHost to use Layer clipping instead of OnPaint() clipping.

chrome/browser/ui/views/dropdown_bar_view.h

Index: chrome/browser/ui/views/dropdown_bar_view.h
diff --git a/chrome/browser/ui/views/dropdown_bar_view.h b/chrome/browser/ui/views/dropdown_bar_view.h
index 64b6951e37b74f667fe774597db67e9a94582494..08bdcdb2637c11f034d540abc433131f11219be5 100644
--- a/chrome/browser/ui/views/dropdown_bar_view.h
+++ b/chrome/browser/ui/views/dropdown_bar_view.h
@@ -26,17 +26,7 @@ class DropdownBarView : public views::AccessiblePaneView,
   explicit DropdownBarView(DropdownBarHost* host);
   ~DropdownBarView() override;
 
-  // Updates the view to let it know where the host is clipping the
-  // dropdown widget (while animating the opening or closing of the widget).
-  void SetAnimationOffset(int offset) override;
-
-  // Returns the offset used while animating.
-  int animation_offset() const { return animation_offset_; }
-
  protected:
-  // views::View:
-  void OnPaint(gfx::Canvas* canvas) override;
-
   // Returns the DropdownBarHost that manages this view.
   DropdownBarHost* host() const { return host_; }
 
@@ -50,12 +40,6 @@ class DropdownBarView : public views::AccessiblePaneView,
   // The dropdown bar host that controls this view.
   DropdownBarHost* host_;
 
-  // While animating, the host clips the widget and draws only the bottom
-  // part of it. The view needs to know the pixel offset at which we are drawing
-  // the widget so that we can draw the curved edges that attach to the toolbar
-  // in the right location.
-  int animation_offset_;
-
   DISALLOW_COPY_AND_ASSIGN(DropdownBarView);
 };
 #endif  // CHROME_BROWSER_UI_VIEWS_DROPDOWN_BAR_VIEW_H_