Mac: Fix theme image drawing when building with >=10.9 SDK.

chrome/browser/ui/cocoa/browser_window_controller_browsertest.mm

Index: chrome/browser/ui/cocoa/browser_window_controller_browsertest.mm
diff --git a/chrome/browser/ui/cocoa/browser_window_controller_browsertest.mm b/chrome/browser/ui/cocoa/browser_window_controller_browsertest.mm
index 7dadf209dc724d622ac07170e5bef3c846673ebe..3241584236b95d0b886c90a60338269cdff30ea3 100644
--- a/chrome/browser/ui/cocoa/browser_window_controller_browsertest.mm
+++ b/chrome/browser/ui/cocoa/browser_window_controller_browsertest.mm
@@ -230,11 +230,15 @@ class BrowserWindowControllerTest : public InProcessBrowserTest {
   void VerifyTrafficLightZOrder() const {
     NSView* contentView = [[controller() window] contentView];
     NSView* rootView = [contentView superview];
-    EXPECT_EQ(contentView, [[rootView subviews] objectAtIndex:0]);
+    NSArray* subviews = [rootView subviews];
+
+    EXPECT_EQ([controller() tabStripBackgroundView],
+              [subviews objectAtIndex:0]);
+    EXPECT_EQ(contentView, [subviews objectAtIndex:1]);
 
     NSView* tabStripView = [controller() tabStripView];
-    if ([[rootView subviews] containsObject:tabStripView])
-      EXPECT_EQ(tabStripView, [[rootView subviews] objectAtIndex:1]);
+    if ([subviews containsObject:tabStripView])
+      EXPECT_EQ(tabStripView, [subviews objectAtIndex:2]);
   }
 
  private: