Explicitely unlock screen orientation when navigating.

content/browser/screen_orientation/screen_orientation_dispatcher_host_impl.cc

Index: content/browser/screen_orientation/screen_orientation_dispatcher_host_impl.cc
diff --git a/content/browser/screen_orientation/screen_orientation_dispatcher_host_impl.cc b/content/browser/screen_orientation/screen_orientation_dispatcher_host_impl.cc
index 0b2fccea286d1296defe6dc3bbba70dd07609a9e..a47784f86143c951948a9bb66edcd0443a936ac9 100644
--- a/content/browser/screen_orientation/screen_orientation_dispatcher_host_impl.cc
+++ b/content/browser/screen_orientation/screen_orientation_dispatcher_host_impl.cc
@@ -5,6 +5,7 @@
 #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"
@@ -55,6 +56,13 @@ bool ScreenOrientationDispatcherHostImpl::OnMessageReceived(
   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) {