canvas2d.drawImage(video) doesn't composite correctly.

Following composite operation should update whole canvas area; SourceIn,
SourceOut, DestinationIn, DestinationAtop, Copy. However, drawImage(video)
doesn't do that unlike drawImage(image) and drawImage(canvas)

In addition, drawImage(video) invalidated a bigger region that needed. This
CL fixes it and add a relevant test.

TEST=fast/canvas/canvas-composite-video.html,
fast/canvas/canvas-composite-repaint-by-all-imagesource.html
BUG=407079

Review URL: https://codereview.chromium.org/530723003

git-svn-id: svn://svn.chromium.org/blink/trunk@183541 bbb929c8-8fbe-4397-9dbb-9b2b20218538