mac: Fix tab dragging visual bug in Yosemite.

chrome/browser/ui/cocoa/browser_window_controller_unittest.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "chrome/browser/ui/cocoa/browser_window_controller.h"
 
 #include "base/mac/mac_util.h"
 #import "base/mac/scoped_nsobject.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/prefs/pref_service.h"
@@ skipping 597 matching lines @@
   EXPECT_EQ(screenFrame.size.height, zoomFrame.size.height);
   EXPECT_EQ(testFrame.origin.x, zoomFrame.origin.x);
   EXPECT_EQ(screenFrame.origin.y, zoomFrame.origin.y);
 }
 
 TEST_F(BrowserWindowControllerTest, TestFindBarOnTop) {
   FindBarBridge bridge(NULL);
   [controller_ addFindBar:bridge.find_bar_cocoa_controller()];
 
   // Test that the Z-order of the find bar is on top of everything.
-  NSArray* subviews = [[[controller_ window] contentView] subviews];
+  NSArray* subviews = [controller_.chromeContentView subviews];
   NSUInteger findBar_index =
       [subviews indexOfObject:[controller_ findBarView]];
   EXPECT_NE(NSNotFound, findBar_index);
   NSUInteger toolbar_index =
       [subviews indexOfObject:[controller_ toolbarView]];
   EXPECT_NE(NSNotFound, toolbar_index);
   NSUInteger bookmark_index =
       [subviews indexOfObject:[controller_ bookmarkView]];
   EXPECT_NE(NSNotFound, bookmark_index);
 
@@ skipping 250 matching lines @@
   testFullscreenWindow_.reset(
       [[NSWindow alloc] initWithContentRect:NSMakeRect(0,0,400,400)
                                   styleMask:NSBorderlessWindowMask
                                     backing:NSBackingStoreBuffered
                                       defer:NO]);
   return testFullscreenWindow_.get();
 }
 @end
 
 /* TODO(???): test other methods of BrowserWindowController */