Add base:: to string16 in chrome_frame/.

chrome_frame/metrics_service.cc

 // 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.
 
 //------------------------------------------------------------------------------
 // Description of the life cycle of a instance of MetricsService.
 //
 //  OVERVIEW
 //
 // A MetricsService instance is created at ChromeFrame startup in
@@ skipping 293 matching lines @@
   // TODO(robertshield): Chrome Frame shouldn't generate a new ID on every run
   // as this apparently breaks some assumptions during metric analysis.
   // See http://crbug.com/117188
   if (client_id_.empty()) {
     const int kGUIDSize = 39;
 
     GUID guid;
     HRESULT guid_result = CoCreateGuid(&guid);
     DCHECK(SUCCEEDED(guid_result));
 
-    string16 guid_string;
+    base::string16 guid_string;
     int result = StringFromGUID2(guid,
                                  WriteInto(&guid_string, kGUIDSize), kGUIDSize);
     DCHECK(result == kGUIDSize);
     client_id_ = WideToUTF8(guid_string.substr(1, guid_string.length() - 2));
   }
   return client_id_;
 }
 
 // static
 void CALLBACK MetricsService::TransmissionTimerProc(HWND window,
@@ skipping 129 matching lines @@
     version += "-F";
     if (!version_info.IsOfficialBuild())
       version.append("-devel");
     return version;
   } else {
     NOTREACHED() << "Unable to retrieve version string.";
   }
 
   return std::string();
 }