Correctly align tab and toolbar backgrounds with the frame background.

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 38ea62c04d85f5750dd043a9817fa767d043887c..7b42ee6fb02833b182c8850fdcb290e28a19c3b1 100644
--- a/chrome/browser/ui/views/tabs/tab.h
+++ b/chrome/browser/ui/views/tabs/tab.h
@@ -154,6 +154,15 @@ class Tab : public gfx::AnimationDelegate,
   // Returns the height for immersive mode tabs.
   static int GetImmersiveHeight();
 
+  // Returns the Y offset within the tab background image to begin drawing at
+  // the top of the active tab bounds.  This is a negative value, which will
+  // result in the top of the tab background image being drawn below the top of
+  // the tab.  None of this offset area is actually visible.
+  //
+  // This is necessary for correct vertical alignment of the frame, tab, and
+  // toolbar images with custom themes.
+  static int GetYOffsetForActiveTabBackground();
+
  private:
   friend class TabTest;
   FRIEND_TEST_ALL_PREFIXES(TabTest, CloseButtonLayout);