Proper rendering of stacked tabs for MD.

chrome/browser/ui/views/tabs/tab.h

Index: chrome/browser/ui/views/tabs/tab.h
diff --git a/chrome/browser/ui/views/tabs/tab.h b/chrome/browser/ui/views/tabs/tab.h
index 74f2fdaa20264df30cb2dc996303950400fbaad6..af3269cfe5e2177a5fb3636fa0cf3cbd32bd315e 100644
--- a/chrome/browser/ui/views/tabs/tab.h
+++ b/chrome/browser/ui/views/tabs/tab.h
@@ -231,15 +231,17 @@ class Tab : public gfx::AnimationDelegate,
   // Invoked from SetData after |data_| has been updated to the new data.
   void DataChanged(const TabRendererData& old);
 
-  // Paint with the normal tab style.
-  void PaintTab(gfx::Canvas* canvas);
+  // Paint with the normal tab style.  If |clip| is non-empty, the tab border
+  // should be clipped against it.
+  void PaintTab(gfx::Canvas* canvas, const gfx::Path& clip);
 
   // Paint with the "immersive mode" light-bar style.
   void PaintImmersiveTab(gfx::Canvas* canvas);
 
   // Paint various portions of the Tab.
-  void PaintInactiveTabBackground(gfx::Canvas* canvas);
-  void PaintTabBackgroundUsingFillId(gfx::Canvas* canvas,
+  void PaintInactiveTabBackground(gfx::Canvas* canvas, const gfx::Path& clip);
+  void PaintTabBackgroundUsingFillId(gfx::Canvas* fill_canvas,
+                                     gfx::Canvas* stroke_canvas,
                                      bool is_active,
                                      int fill_id,
                                      bool has_custom_image,