We do not pass enums by conts references. This CL fixes style errors introduced

content/shell/shell_web_contents_view_delegate_mac.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.
 
 #include "content/shell/shell_web_contents_view_delegate.h"
 
 #import  <Cocoa/Cocoa.h>
 
 #include "content/public/browser/devtools_http_handler.h"
 #include "content/public/browser/render_process_host.h"
@@ skipping 75 matching lines @@
 ShellWebContentsViewDelegate::ShellWebContentsViewDelegate(
     WebContents* web_contents)
     : web_contents_(web_contents) {
 }
 
 ShellWebContentsViewDelegate::~ShellWebContentsViewDelegate() {
 }
 
 void ShellWebContentsViewDelegate::ShowContextMenu(
     const ContextMenuParams& params,
-    const ContextMenuSourceType& type) {
+    ContextMenuSourceType type) {
   params_ = params;
   bool has_link = !params_.unfiltered_link_url.is_empty();
   bool has_selection = ! params_.selection_text.empty();
 
   NSMenu* menu = [[[NSMenu alloc] initWithTitle:@""] autorelease];
   ShellContextMenuDelegate* delegate =
       [[ShellContextMenuDelegate alloc] initWithDelegate:this];
   [menu setDelegate:delegate];
   [menu setAutoenablesItems:NO];
 
@@ skipping 170 matching lines @@
   return NULL;
 }
 
 NSObject<RenderWidgetHostViewMacDelegate>*
 ShellWebContentsViewDelegate::CreateRenderWidgetHostViewDelegate(
     content::RenderWidgetHost* render_widget_host) {
   return NULL;
 }
 
 }  // namespace content