GitLab

- Full rewrite of the MediaFoundation implementation video part to use
IMFCaptureEngine
- Implementation of takePhoto, setPhotoOptions and getPhotoCapabilities
- takePhoto triggers a still image capture with the highest available
resolution without stopping the video stream thanks to IMFCaptureEngine

TEST=adapted video_capture_device_unittest.cc and
webrtc_image_capture_browsertest.cc; launch Chrome with
--force-mediafoundation on Win8+ and capture video using
e.g. https://webrtc.github.io/samples/src/content/getusermedia/gum/

R=mcasas@chromium.org

Bug: 730068
Change-Id: Ib8e7f475d8120a63dd08c7b215c1eaf2c6f3d800
Reviewed-on: https://chromium-review.googlesource.com/734042
Commit-Queue: Christian Fremerey <chfremer@chromium.org>
Reviewed-by: Miguel Casas <mcasas@chromium.org>
Reviewed-by: Christian Fremerey <chfremer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521435}