<webview>: Move back, forward, canGoBack, canGoForward, go from content to chrome

chrome/browser/extensions/api/webview/webview_api.cc

 // Copyright (c) 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 "chrome/browser/extensions/api/webview/webview_api.h"
 
 #include "chrome/browser/extensions/tab_helper.h"
 #include "chrome/browser/webview/webview_guest.h"
 #include "chrome/common/extensions/api/webview.h"
 #include "content/public/browser/render_process_host.h"
@@ skipping 62 matching lines @@
   if (error.empty())
     SetResult(result.DeepCopy());
   WebviewExecuteCodeFunction::OnExecuteCodeFinished(error, on_page_id, on_url,
                                                     result);
 }
 
 bool WebviewInsertCSSFunction::ShouldInsertCSS() const {
   return true;
 }
 
+WebviewGoFunction::WebviewGoFunction() {
+}
+
+WebviewGoFunction::~WebviewGoFunction() {
+}
+
+bool WebviewGoFunction::RunImpl() {
+  int instance_id;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(0, &instance_id));
+
+  int relative_index;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetInteger(1, &relative_index));
+
+  chrome::WebViewGuest* guest = chrome::WebViewGuest::From(
+    render_view_host()->GetProcess()->GetID(), instance_id);
+  if (!guest)
+    return false;
+
+  guest->Go(relative_index);
+  return true;
+}