Coverity: Pass parameters by reference.

chrome/browser/extensions/extension_tabs_module.cc

 // Copyright (c) 2011 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/extensions/extension_tabs_module.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/base64.h"
@@ skipping 52 matching lines @@
                        TabContentsWrapper** contents,
                        int* tab_index, std::string* error_message);
 
 // Takes |url_string| and returns a GURL which is either valid and absolute
 // or invalid. If |url_string| is not directly interpretable as a valid (it is
 // likely a relative URL) an attempt is made to resolve it. |extension| is
 // provided so it can be resolved relative to its extension base
 // (chrome-extension://<id>/). Using the source frame url would be more correct,
 // but because the api shipped with urls resolved relative to their extension
 // base, we decided it wasn't worth breaking existing extensions to fix.
-static GURL ResolvePossiblyRelativeURL(std::string url_string,
+static GURL ResolvePossiblyRelativeURL(const std::string& url_string,
                                        const Extension* extension);
 
 // Return the type name for a browser window type.
 static std::string GetWindowTypeText(Browser::Type type);
 
 int ExtensionTabUtil::GetWindowId(const Browser* browser) {
   return browser->session_id().id();
 }
 
 int ExtensionTabUtil::GetTabId(const TabContents* tab_contents) {
@@ skipping 1137 matching lines @@
 }
 
 void DetectTabLanguageFunction::GotLanguage(const std::string& language) {
   result_.reset(Value::CreateStringValue(language.c_str()));
   SendResponse(true);
 
   Release();  // Balanced in Run()
 }
 
 // static helpers
+// TODO(jhawkins): Move these to unnamed namespace and remove static modifier.
 
 static Browser* GetBrowserInProfileWithId(Profile* profile,
                                           const int window_id,
                                           bool include_incognito,
                                           std::string* error_message) {
   Profile* incognito_profile =
       include_incognito && profile->HasOffTheRecordProfile() ?
           profile->GetOffTheRecordProfile() : NULL;
   for (BrowserList::const_iterator browser = BrowserList::begin();
        browser != BrowserList::end(); ++browser) {
@@ skipping 32 matching lines @@
   if ((type & Browser::TYPE_POPUP) == Browser::TYPE_POPUP)
     return keys::kWindowTypeValuePopup;
 
   if ((type & Browser::TYPE_APP) == Browser::TYPE_APP)
     return keys::kWindowTypeValueApp;
 
   DCHECK(type == Browser::TYPE_NORMAL);
   return keys::kWindowTypeValueNormal;
 }
 
-static GURL ResolvePossiblyRelativeURL(std::string url_string,
+static GURL ResolvePossiblyRelativeURL(const std::string& url_string,
                                        const Extension* extension) {
   GURL url = GURL(url_string);
   if (!url.is_valid())
     url = extension->GetResourceURL(url_string);
 
   return url;
 }