Explicitely unlock screen orientation when navigating.

content/browser/screen_orientation/screen_orientation_dispatcher_host_impl.h

 // 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.
 
 #ifndef CONTENT_BROWSER_SCREEN_ORIENTATION_SCREEN_ORIENTATION_DISPATCHER_HOST_IMPL_H_
 #define CONTENT_BROWSER_SCREEN_ORIENTATION_SCREEN_ORIENTATION_DISPATCHER_HOST_IMPL_H_
 
 #include "content/public/browser/screen_orientation_dispatcher_host.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "third_party/WebKit/public/platform/WebLockOrientationError.h"
@@ skipping 17 matching lines @@
 
   // ScreenOrientationDispatcherHost:
   virtual void NotifyLockSuccess(int request_id) OVERRIDE;
   virtual void NotifyLockError(int request_id,
                                blink::WebLockOrientationError error) OVERRIDE;
   virtual void OnOrientationChange() OVERRIDE;
 
   // WebContentsObserver:
   virtual bool OnMessageReceived(const IPC::Message&,
                                  RenderFrameHost* render_frame_host) OVERRIDE;
+  virtual void DidNavigateMainFrame(const LoadCommittedDetails& details,
+                                    const FrameNavigateParams& params) OVERRIDE;
 
  private:
   void OnLockRequest(RenderFrameHost* render_frame_host,
                      blink::WebScreenOrientationLockType orientation,
                      int request_id);
   void OnUnlockRequest(RenderFrameHost* render_frame_host);
 
   // Returns a RenderFrameHost if the request_id is still valid and the
   // associated RenderFrameHost still exists. Returns NULL otherwise.
   RenderFrameHost* GetRenderFrameHostForRequestID(int request_id);
@@ skipping 13 matching lines @@
   };
   // current_lock_ will be NULL if there are no current lock.
   LockInformation* current_lock_;
 
   DISALLOW_COPY_AND_ASSIGN(ScreenOrientationDispatcherHostImpl);
 };
 
 }  // namespace content
 
 #endif // CONTENT_BROWSER_SCREEN_ORIENTATION_SCREEN_ORIENTATION_DISPATCHER_HOST_IMPL_H_