Merge 279078 "Video Capture: Allow 0 fps frame rates to be deser..."

Merge 279078 "Video Capture: Allow 0 fps frame rates to be deser..."

> Video Capture: Allow 0 fps frame rates to be deserializable
> 
> Some webcams, notably the Win XSplit broadcaster, 
> indicate 0 fps frame rate when they are not started/
> configured. This rate is not deserializable 
> (because is not IsValid()) [1]. This CL allows 
> supported formats with 0 fps to be received via 
> IPC.
> 
> XSplit walkthrough before-after:
> 
> Currently when XSplit lists 0 fps, the message
> cannot be deserialized from the IPC and is 
> discarded; getUserMedia constraint resolution 
> @MediaStreamVideoCapturerSource never 
> progresses since is expecting that message.
> 
> With this change, 0 fps will be used, and since
> for unconfigured XSplit this is the only frame 
> rate, it's used (unless the user constrains it 
> via Mandatory constraint). When the 0 fps 
> selected format is passed to the 
> VideoCaptureDeviceWin to be used, this ignores
> it (since is zero), and the capture happens
> at whatever frame rate is native to the
> source. And then we see an XSplit picture
> indicating this fact. When streaming starts,
> the picture is substituted with the feed.
> 
> BUG=383949
> 
> [1] https://code.google.com/p/chromium/codesearch#chromium/src/media/video/capture/video_capture_types.cc&sq=package:chromium&type=cs&q=IsValid%20video%20&l=26
> 
> Review URL: https://codereview.chromium.org/332863002

TBR=mcasas@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=287599

[vrk (LEFT CHROMIUM), 2014-08-05 21:07:42]

Committed patchset #1 manually as r287599 (tree was closed).