webrtc on Mac problematic in videocapturer due to signed/unsigned issue

What steps will reproduce the problem?
1. Built a /branches/3.2/ build of webrtc from rev 1671 using DEPS with 
libjingle_rev=101.
2. On Mac, video capture setup fails to complete successfully.

What is the expected output? What do you see instead?
- Expect to have video capture active. Instead, wind up with an infinite loop 
down in webrtcvideocapturer.cc

Please provide any additional information below.
- At least one issue exists regardless of a final 'solution' to Mac 
support...see rev 101 of webrtcvideocapturer.cc:182 
WebRtcVideoCapturer::Init(const Device& device)

WebRtc_UWord32 num_caps = info->NumberOfCapabilities(vcm_id);
On Mac, this is problematic. The unsigned 32-bit word here is assigned while 
video_capture_qtkit_info.mm from webrtc is returning a "-1" due to 
non-supported capabilities situation. This value is then used in a for() loop. 
At a minimum, this value should be a signed-value and checked against -1 before 
being used in the for() loop.

Original issue reported on code.google.com by rwo...@gocast.it on 25 Feb 2012 at 1:08

birdca / libjingle

webrtc on Mac problematic in videocapturer due to signed/unsigned issue #314