Coverity PASS_BY_VALUE fix.

chrome/browser/ui/cocoa/extensions/shell_window_cocoa.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 "chrome/browser/ui/cocoa/extensions/shell_window_cocoa.h"
 
 #include "base/sys_string_conversions.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/cocoa/browser_window_utils.h"
 #include "chrome/browser/ui/cocoa/extensions/extension_view_mac.h"
 #include "chrome/common/extensions/extension.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_view.h"
 #import "ui/base/cocoa/underlay_opengl_hosting_window.h"
 
 @implementation ShellWindowController
 
 @synthesize shellWindow = shellWindow_;
 
 - (void)windowWillClose:(NSNotification*)notification {
   if (shellWindow_)
     shellWindow_->WindowWillClose();
 }
 
 @end
 
 ShellWindowCocoa::ShellWindowCocoa(Profile* profile,
                                    const extensions::Extension* extension,
                                    const GURL& url,
-                                   const ShellWindow::CreateParams params)
+                                   const ShellWindow::CreateParams& params)
     : ShellWindow(profile, extension, url),
       attention_request_id_(0) {
   NSRect rect = NSMakeRect(params.bounds.x(), params.bounds.y(),
                            params.bounds.width(), params.bounds.height());
   NSUInteger styleMask = NSTitledWindowMask | NSClosableWindowMask |
                          NSMiniaturizableWindowMask | NSResizableWindowMask;
   scoped_nsobject<NSWindow> window([[UnderlayOpenGLHostingWindow alloc]
       initWithContentRect:rect
                 styleMask:styleMask
                   backing:NSBackingStoreBuffered
@@ skipping 129 matching lines @@
 }
 
 NSWindow* ShellWindowCocoa::window() const {
   return [window_controller_ window];
 }
 
 // static
 ShellWindow* ShellWindow::CreateImpl(Profile* profile,
                                      const extensions::Extension* extension,
                                      const GURL& url,
-                                     const ShellWindow::CreateParams params) {
+                                     const ShellWindow::CreateParams& params) {
   return new ShellWindowCocoa(profile, extension, url, params);
 }