Explicitely unlock screen orientation when navigating.

content/browser/screen_orientation/screen_orientation_dispatcher_host_impl.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/browser/screen_orientation/screen_orientation_dispatcher_host_impl.h"
 
 #include "content/common/screen_orientation_messages.h"
+#include "content/public/browser/navigation_details.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/render_widget_host.h"
 #include "content/public/browser/screen_orientation_provider.h"
 #include "content/public/browser/web_contents.h"
 #include "third_party/WebKit/public/platform/WebScreenInfo.h"
 
 namespace content {
 
@@ skipping 30 matching lines @@
   IPC_BEGIN_MESSAGE_MAP_WITH_PARAM(ScreenOrientationDispatcherHostImpl, message,
                                    render_frame_host)
     IPC_MESSAGE_HANDLER(ScreenOrientationHostMsg_LockRequest, OnLockRequest)
     IPC_MESSAGE_HANDLER(ScreenOrientationHostMsg_Unlock, OnUnlockRequest)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
 
   return handled;
 }
 
+void ScreenOrientationDispatcherHostImpl::DidNavigateMainFrame(
+    const LoadCommittedDetails& details, const FrameNavigateParams& params) {
+  if (!provider_ || details.is_in_page)
+    return;
+  provider_->UnlockOrientation();
+}
+
 RenderFrameHost*
 ScreenOrientationDispatcherHostImpl::GetRenderFrameHostForRequestID(
     int request_id) {
   if (!current_lock_ || current_lock_->request_id != request_id)
     return NULL;
 
   return RenderFrameHost::FromID(current_lock_->process_id,
                                  current_lock_->routing_id);
 }
 
@@ skipping 61 matching lines @@
                     blink::WebLockOrientationErrorCanceled);
   }
 
   if (!provider_)
     return;
 
   provider_->UnlockOrientation();
 }
 
 }  // namespace content