Convert string16 to base::string16 in content.

content/shell/browser/shell_mac.mm

 // Copyright 2013 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 "content/shell/browser/shell.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #import "base/mac/scoped_nsobject.h"
@@ skipping 256 matching lines @@
   }
   NSView* web_view = web_contents_->GetView()->GetNativeView();
   NSRect frame = NSMakeRect(0, 0, content_size.width(), content_size.height());
   [web_view setFrame:frame];
 }
 
 void Shell::PlatformResizeSubViews() {
   // Not needed; subviews are bound.
 }
 
-void Shell::PlatformSetTitle(const string16& title) {
+void Shell::PlatformSetTitle(const base::string16& title) {
   if (headless_)
     return;
 
   NSString* title_string = base::SysUTF16ToNSString(title);
   [window_ setTitle:title_string];
 }
 
 void Shell::Close() {
   if (headless_)
     delete this;
@@ skipping 39 matching lines @@
         [[event.os_event characters] isEqual:@"l"]) {
       [window_ makeFirstResponder:url_edit_view_];
       return;
     }
 
     [[NSApp mainMenu] performKeyEquivalent:event.os_event];
   }
 }
 
 }  // namespace content