Add support for shared texture and external BeginFrame in OSR mode (issue #1006)

- Add CefWindowInfo::shared_texture_enabled and
  CefRenderHandler::OnAcceleratedPaint for shared texture support. Currently
  only supported on Windows (D3D11).
- Add CefWindowInfo::external_begin_frame_enabled and
  CefBrowserHost::SendExternalBeginFrame for external begin frame support.

libcef_dll/ctocpp/browser_host_ctocpp.h

@@ -9,7 +9,7 @@
 // implementations. See the translator.README.txt file in the tools directory
 // for more information.
 //
-// $hash=39ab8db08e667fac8e6dccffaa99935d8aa7d4b5$
+// $hash=0a61852aa1a8c8c808e9d2258e09a0fa341056e0$
 //
 
 #ifndef CEF_LIBCEF_DLL_CTOCPP_BROWSER_HOST_CTOCPP_H_
@@ -86,6 +86,7 @@ class CefBrowserHostCToCpp : public CefCToCppRefCounted<CefBrowserHostCToCpp,
   void WasHidden(bool hidden) OVERRIDE;
   void NotifyScreenInfoChanged() OVERRIDE;
   void Invalidate(PaintElementType type) OVERRIDE;
+  void SendExternalBeginFrame() OVERRIDE;
   void SendKeyEvent(const CefKeyEvent& event) OVERRIDE;
   void SendMouseClickEvent(const CefMouseEvent& event,
                            MouseButtonType type,