Filter in Capture device with pixel format RGB3 to make WebcamStudio virtual camera visible in device list
Filter in Capture device with pixel format RGB3 to make WebcamStudio virtual camera visible in device list

BUG=434352
TEST=1. VideoCaptureDeviceTest in media_unittests to make sure nothing is broken;

2. Install WebcamStudio and v4l2loopback.dkms. Run the WebcamStudio, and input some graph through the virtual camera. Go to website "https://src.chromium.org/svn/trunk/src/chrome/test/data/webrtc/manual/peerconnection.html", make sure after clicking "get devices", the virtual camera is in the list to choose, and after clicking "Request GetUserMedia", the graph you injected into the virtual camera is shown in the local preview area.

Review URL: https://codereview.chromium.org/1040943003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#323071}

Fireblend/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Just-D/chromium-1,Pluto-tv/chromium-crosswalk,ltilve/chromium,chuan9/chromium-crosswalk,hgl888/chromium-crosswalk,hgl888/chromium-crosswalk,Chilledheart/chromium,axinging/chromium-crosswalk,fujunwei/chromium-crosswalk,axinging/chromium-crosswalk,Chilledheart/chromium,axinging/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,axinging/chromium-crosswalk,Fireblend/chromium-crosswalk,Pluto-tv/chromium-crosswalk,ltilve/chromium,Chilledheart/chromium,chuan9/chromium-crosswalk,Chilledheart/chromium,fujunwei/chromium-crosswalk,ltilve/chromium,ltilve/chromium,hgl888/chromium-crosswalk,hgl888/chromium-crosswalk,axinging/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,fujunwei/chromium-crosswalk,chuan9/chromium-crosswalk,chuan9/chromium-crosswalk,ltilve/chromium,Chilledheart/chromium,axinging/chromium-crosswalk,Fireblend/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,hgl888/chromium-crosswalk,Just-D/chromium-1,TheTypoMaster/chromium-crosswalk,axinging/chromium-crosswalk,Pluto-tv/chromium-crosswalk,fujunwei/chromium-crosswalk,fujunwei/chromium-crosswalk,axinging/chromium-crosswalk,Just-D/chromium-1,Fireblend/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,chuan9/chromium-crosswalk,Fireblend/chromium-crosswalk,chuan9/chromium-crosswalk,Just-D/chromium-1,PeterWangIntel/chromium-crosswalk,Just-D/chromium-1,Just-D/chromium-1,ltilve/chromium,Just-D/chromium-1,Just-D/chromium-1,Chilledheart/chromium,Fireblend/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,axinging/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,Fireblend/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,ltilve/chromium,PeterWangIntel/chromium-crosswalk,hgl888/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,ltilve/chromium,fujunwei/chromium-crosswalk,Chilledheart/chromium,Pluto-tv/chromium-crosswalk,hgl888/chromium-crosswalk,hgl888/chromium-crosswalk,chuan9/chromium-crosswalk,Fireblend/chromium-crosswalk,axinging/chromium-crosswalk,fujunwei/chromium-crosswalk,axinging/chromium-crosswalk,Fireblend/chromium-crosswalk,fujunwei/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,Just-D/chromium-1,PeterWangIntel/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,chuan9/chromium-crosswalk,Chilledheart/chromium,ltilve/chromium,hgl888/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Chilledheart/chromium,fujunwei/chromium-crosswalk,chuan9/chromium-crosswalk