Convert string16 to base::string16 in content.

content/renderer/render_view_browsertest_mac.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 "base/strings/string16.h"
 #include "base/strings/string_util.h"
 #include "content/public/browser/native_web_keyboard_event.h"
 #include "content/public/test/render_view_test.h"
 #include "content/renderer/render_view_impl.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 68 matching lines @@
   );
   #undef HTML
 
   WebPreferences prefs;
   prefs.enable_scroll_animator = false;
 
   RenderViewImpl* view = static_cast<RenderViewImpl*>(view_);
   view->OnUpdateWebPreferences(prefs);
 
   const int kMaxOutputCharacters = 1024;
-  string16 output;
+  base::string16 output;
 
   NSEvent* arrowDownKeyDown = CmdDeadKeyEvent(NSKeyDown, kVK_DownArrow);
   NSEvent* arrowUpKeyDown = CmdDeadKeyEvent(NSKeyDown, kVK_UpArrow);
 
   // First test when javascript does not eat keypresses -- should scroll.
   view->set_send_content_state_immediately(true);
   LoadHTML(kRawHtml);
   render_thread_->sink().ClearMessages();
 
   const char* kArrowDownScrollDown = "40,false,false,true,false\n10144\np1";
@@ skipping 32 matching lines @@
   view->OnSetEditCommandsForNextKeyEvent(
       EditCommands(1, EditCommand("moveToBeginningOfDocument", "")));
   SendNativeKeyEvent(NativeWebKeyboardEvent(arrowUpKeyDown));
   ProcessPendingMessages();
   ExecuteJavaScript("scroll.textContent = window.pageYOffset");
   output = GetMainFrame()->contentAsText(kMaxOutputCharacters);
   EXPECT_EQ(kArrowUpNoScroll, UTF16ToASCII(output));
 }
 
 }  // namespace content