[Mac] Fix background color of tab contents area when CoreAnimation is enabled.

chrome/browser/ui/cocoa/tab_contents/tab_contents_controller.mm

Index: chrome/browser/ui/cocoa/tab_contents/tab_contents_controller.mm
diff --git a/chrome/browser/ui/cocoa/tab_contents/tab_contents_controller.mm b/chrome/browser/ui/cocoa/tab_contents/tab_contents_controller.mm
index 7e91b1799e90fe1045d54c781c91d8b07917858f..7eb9a3a4a275171ba7c574ca7cd1c2f3761c5ff6 100644
--- a/chrome/browser/ui/cocoa/tab_contents/tab_contents_controller.mm
+++ b/chrome/browser/ui/cocoa/tab_contents/tab_contents_controller.mm
@@ -188,6 +188,11 @@ class FullscreenObserver : public WebContentsObserver {
   }
   [contentsNativeView setAutoresizingMask:NSViewWidthSizable|
                                           NSViewHeightSizable];
+
+  // TODO(miu): The following can be removed once we use a CALayer in
+  // TabContentsContainerView.  http://crbug.com/354598
+  [contentsContainer setNeedsDisplay:YES];
+
   // The rendering path with overlapping views disabled causes bugs when
   // transitioning between composited and non-composited mode.
   // http://crbug.com/279472