Coverity PASS_BY_VALUE fix.

chrome/browser/ui/cocoa/extensions/shell_window_cocoa.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_COCOA_EXTENSIONS_SHELL_WINDOW_COCOA_H_
 #define CHROME_BROWSER_UI_COCOA_EXTENSIONS_SHELL_WINDOW_COCOA_H_
 #pragma once
 
 #import <Cocoa/Cocoa.h>
 
@@ skipping 15 matching lines @@
 @property(assign, nonatomic) ShellWindowCocoa* shellWindow;
 
 @end
 
 // Cocoa bridge to ShellWindow.
 class ShellWindowCocoa : public ShellWindow {
  public:
   ShellWindowCocoa(Profile* profile,
                    const extensions::Extension* extension,
                    const GURL& url,
-                   const CreateParams params);
+                   const CreateParams& params);
 
   // BaseWindow implementation.
   virtual bool IsActive() const OVERRIDE;
   virtual bool IsMaximized() const OVERRIDE;
   virtual bool IsMinimized() const OVERRIDE;
   virtual bool IsFullscreen() const OVERRIDE;
   virtual gfx::NativeWindow GetNativeWindow() OVERRIDE;
   virtual gfx::Rect GetRestoredBounds() const OVERRIDE;
   virtual gfx::Rect GetBounds() const OVERRIDE;
   virtual void Show() OVERRIDE;
@@ skipping 17 matching lines @@
 
   NSWindow* window() const;
 
   scoped_nsobject<ShellWindowController> window_controller_;
   NSInteger attention_request_id_;  // identifier from requestUserAttention
 
   DISALLOW_COPY_AND_ASSIGN(ShellWindowCocoa);
 };
 
 #endif  // CHROME_BROWSER_UI_COCOA_EXTENSIONS_SHELL_WINDOW_COCOA_H_