ui: Remove use of bitmaps when painting tab backgrounds.

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 7b7bc644e81e50785ca15f69330a514f3126bb59..d5fcd4d0abe6a90f420044cf8b2dc33032270faf 100644
--- a/chrome/browser/ui/views/tabs/tab.h
+++ b/chrome/browser/ui/views/tabs/tab.h
@@ -235,11 +235,21 @@ class Tab : public gfx::AnimationDelegate,
   // Paints a tab background using the image defined by |fill_id| at the
   // provided offset. If |fill_id| is 0, it will fall back to using the solid
   // color defined by the theme provider and ignore the offset.
-  void PaintTabBackgroundUsingFillId(gfx::Canvas* fill_canvas,
-                                     gfx::Canvas* stroke_canvas,
-                                     bool is_active,
-                                     int fill_id,
-                                     int y_offset);
+  void PaintTabBackground(gfx::Canvas* canvas,
+                          bool active,
+                          int fill_id,
+                          int y_offset,
+                          const gfx::Path* clip);
+
+  // Helper methods for PaintTabBackground.
+  void PaintTabBackgroundFill(gfx::Canvas* canvas,
+                              const gfx::Path& fill_path,
+                              bool is_active,
+                              int fill_id,
+                              int y_offset);
+  void PaintTabBackgroundStroke(gfx::Canvas* canvas,
+                                const gfx::Path& fill_path,
+                                bool active);
 
   // Paints the pinned tab title changed indicator and |favicon_|. |favicon_|
   // may be null. |favicon_draw_bounds| is |favicon_bounds_| adjusted for rtl