Instant: Use only one hidden WebContents per profile.

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

 // Copyright 2013 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/tab_contents/preview_drop_shadow_view.h"
+#import "chrome/browser/ui/cocoa/tab_contents/overlay_drop_shadow_view.h"
 
 #include "grit/theme_resources.h"
 #include "ui/base/resource/resource_bundle.h"
 
-@implementation PreviewDropShadowView
+@implementation OverlayDropShadowView
 
 + (CGFloat)preferredHeight {
   ResourceBundle& rb = ResourceBundle::GetSharedInstance();
   NSImage* shadowImage =
-      rb.GetNativeImageNamed(IDR_PREVIEW_DROP_SHADOW).ToNSImage();
+      rb.GetNativeImageNamed(IDR_OVERLAY_DROP_SHADOW).ToNSImage();
   return [shadowImage size].height;
 }
 
 - (void)drawRect:(NSRect)rect {
   ResourceBundle& rb = ResourceBundle::GetSharedInstance();
   NSRect bounds = [self bounds];
 
   // Draw the shadow.
   NSImage* shadowImage =
-      rb.GetNativeImageNamed(IDR_PREVIEW_DROP_SHADOW).ToNSImage();
+      rb.GetNativeImageNamed(IDR_OVERLAY_DROP_SHADOW).ToNSImage();
   [shadowImage drawInRect:bounds
                  fromRect:NSZeroRect
                 operation:NSCompositeSourceOver
                  fraction:1.0];
 }
 
 @end