Use explicit WebString conversions in remaining content files

content/renderer/render_frame_proxy.cc

 // Copyright 2014 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/renderer/render_frame_proxy.h"
 
 #include <stdint.h>
 #include <map>
 #include <utility>
 
@@ skipping 441 matching lines @@
 
 void RenderFrameProxy::forwardPostMessage(
     blink::WebLocalFrame* source_frame,
     blink::WebRemoteFrame* target_frame,
     blink::WebSecurityOrigin target_origin,
     blink::WebDOMMessageEvent event) {
   DCHECK(!web_frame_ || web_frame_ == target_frame);
 
   FrameMsg_PostMessage_Params params;
   params.is_data_raw_string = false;
-  params.data = event.data().toString();
-  params.source_origin = event.origin();
+  params.data = event.data().toString().utf16();
+  params.source_origin = event.origin().utf16();
   if (!target_origin.isNull())
-    params.target_origin = target_origin.toString();
+    params.target_origin = target_origin.toString().utf16();
 
   params.message_ports =
       WebMessagePortChannelImpl::ExtractMessagePortIDs(event.releaseChannels());
 
   // Include the routing ID for the source frame (if one exists), which the
   // browser process will translate into the routing ID for the equivalent
   // frame in the target process.
   params.source_routing_id = MSG_ROUTING_NONE;
   if (source_frame) {
     RenderFrameImpl* source_render_frame =
@@ skipping 65 matching lines @@
                                     blink::WebLocalFrame* source) {
   int source_routing_id = RenderFrameImpl::FromWebFrame(source)->GetRoutingID();
   Send(new FrameHostMsg_AdvanceFocus(routing_id_, type, source_routing_id));
 }
 
 void RenderFrameProxy::frameFocused() {
   Send(new FrameHostMsg_FrameFocused(routing_id_));
 }
 
 }  // namespace