Make canvases fall out of display list mode when used as a source image

Bug fixed by overriding newImageSnapshot in RecordingImageBufferSurface

BUG=428498
TEST=see bug for list of layout tests

Review URL: https://codereview.chromium.org/685323002

git-svn-id: svn://svn.chromium.org/blink/trunk@184610 bbb929c8-8fbe-4397-9dbb-9b2b20218538