Move out DidStartProvisionalLoad from WebContentsImpl into Navigator.

content/browser/renderer_host/navigator_observer.h

Index: content/browser/renderer_host/navigator_observer.h
diff --git a/content/browser/renderer_host/navigator_observer.h b/content/browser/renderer_host/navigator_observer.h
new file mode 100644
index 0000000000000000000000000000000000000000..eae4046ec88c7b32f3d0ac128c8dbfa15d59fdcd
--- /dev/null
+++ b/content/browser/renderer_host/navigator_observer.h
@@ -0,0 +1,42 @@
+// 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_OBSERVER_H_
+#define CONTENT_BROWSER_RENDERER_HOST_NAVIGATOR_OBSERVER_H_
+
+#include "ipc/ipc_listener.h"
+
+class GURL;
+
+namespace content {
+
+class RenderFrameHost;
+
+// An observer API which is a subset of WebContentsObserver but restricted
+// to navigation related events.
+class NavigatorObserver { //: public IPC::Listener {
+
+ public:
+  virtual void DidStartProvisionalLoad(
+      int64 frame_id,
+      int64 parent_frame_id,
+      bool is_main_frame,
+      const GURL& validated_url,
+      bool is_error_page,
+      bool is_iframe_srcdoc,
+      RenderFrameHost* render_frame_host) {}
+
+  virtual void ProvisionalChangeToMainFrameUrl(
+      const GURL& url,
+      RenderFrameHost* render_frame_host) {}
+
+  virtual void NavigationStateChanged(unsigned changed_flags) {}
+
+ private:
+
+};
+
+}
+
+#endif   // CONTENT_BROWSER_RENDERER_HOST_NAVIGATOR_OBSERVER_H_