The VideoFrameCompositor currently ignores calls to PaintSingleFrame()
if the passed frame is the same as the last frame.

StreamTextureWrapper's (STW) GetCurrentFrame() always returns the same
frame, whilst the underlying texture information has been updated. This
means that it is impossible to use STW's frame with the
PaintSingleFrame() method.

This change adds a "repaint_duplicate_frame" boolean to the
PaintSingleFrame() method, allowing the MediaPlayerRendererClient to
pass the STW's frame directly.

Instead of using the VideoRendererSink interface:
It would have been possible to have STW implement the
VideoFrameProvider interface. This meant that WMPI would have had to
own a STW and create a different VideoLayer, which would have been
more complex to understand, and likely harder to maintain.

Instead of using the PaintSingleFrame method:
It would have also been possible to have STW implement the
RenderCallback interface. However, this would lead to issues due the
different rate at which Render() is called, versus the rate at which
MediaPlayer actuall outputs frames (and would probably degrade
performance).

BUG=636002

Review-Url: https://codereview.chromium.org/2239163002
Cr-Commit-Position: refs/heads/master@{#411773}