Coverity: Pass parameters by reference.

chrome/browser/accessibility/browser_accessibility_win.h

 // Copyright (c) 2010 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_ACCESSIBILITY_BROWSER_ACCESSIBILITY_WIN_H_
 #define CHROME_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_WIN_H_
 #pragma once
 
 #include <atlbase.h>
 #include <atlcom.h>
@@ skipping 446 matching lines @@
   // bitmasks defined in webkit/glue/webaccessibility.h.
   void InitRoleAndState();
 
   // Retrieve the string value of an attribute from the attribute map and
   // if found and nonempty, allocate a new BSTR (with SysAllocString)
   // and return S_OK. If not found or empty, return S_FALSE.
   HRESULT GetAttributeAsBstr(
       WebAccessibility::Attribute attribute, BSTR* value_bstr);
 
   // Escape a string like it would be escaped for a URL or HTML form.
-  string16 Escape(string16 str);
+  string16 Escape(const string16& str);
 
   // Get the text of this node for the purposes of IAccessibleText - it may
   // be the name, it may be the value, etc. depending on the role.
   const string16& TextForIAccessibleText();
 
   // Search forwards (direction == 1) or backwards (direction == -1) from
   // the given offset until the given IAccessible2 boundary (like word,
   // sentence) is found, and return its offset.
   LONG FindBoundary(const string16& text,
                     IA2TextBoundaryType boundary,
                     LONG start_offset,
                     LONG direction);
 
   // IAccessible role and state.
   int32 ia_role_;
   int32 ia_state_;
 
   // IAccessible2 role and state.
   int32 ia2_role_;
   int32 ia2_state_;
 
   // Give BrowserAccessibility::Create access to our constructor.
   friend class BrowserAccessibility;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserAccessibilityWin);
 };
 
 #endif  // CHROME_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_WIN_H_