Move out DidStartProvisionalLoad from WebContentsImpl into Navigator.

content/browser/renderer_host/navigator.h

+// 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.
+
+#ifndef CONTENT_BROWSER_RENDERER_HOST_NAVIGATOR_H_
+#define CONTENT_BROWSER_RENDERER_HOST_NAVIGATOR_H_
+
+#include "base/i18n/rtl.h"
+
+class GURL;
+
+namespace content {
+
+class NavigationControllerImpl;
+class NavigatorObserver;
+class RenderFrameHost;
+
+class Navigator {
+ public:
+  explicit Navigator(
+      NavigationControllerImpl* nav_controller,

[Charlie Reis, 2013/10/17 00:17:25]

nit: This looks like it can fit on the previous line.

+      NavigatorObserver* observer);
+
+  // The RenderFrame started a provisional load.
+  void DidStartProvisionalLoad(
+      RenderFrameHost* render_frame_host,

[Charlie Reis, 2013/10/17 00:17:25]

Same here.

+      int64 frame_id,
+      int64 parent_frame_id,
+      bool main_frame,
+      const GURL& url);
+
+ private:
+  NavigationControllerImpl* controller_;
+
+  NavigatorObserver* observer_;

[Charlie Reis, 2013/10/17 00:17:25]

Perhaps this should be an ObserverList, as in WebContentsImpl?

+};
+
+}
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_NAVIGATOR_H_