Remove legacy weirdness in Merge::Downsample

In practice, this will have only marginal effect. The length_limit
was increased from 6.7 ms to 10 ms. This is compared with the
input_length, which is equal to the decoded frame size. Thus,
this change will only affect encoded frame sizes in this range
(including 10 ms).

BUG=2696
R=tina.legrand@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/9969004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5700 4adac7df-926f-26a2-2b94-8c16560cd09d
Fix a bug where network freeze during CNG causes delay

Wrote a new NetEq unit test to test a network freeze during comfort
noise playout. The network freezes and resumes during the silence
period, and then resumes speech. It was verified that the delay
increased due to the freeze, and this CL contains a fix for that
problem.

BUG=2995
R=turaj@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/9849004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5701 4adac7df-926f-26a2-2b94-8c16560cd09d
Add support for YUV4MPEG file reading to tools files.

This CL adds support for reading .y4m files to the infra in
video_quality_analysis.cc, adding new functions 
ExtractFrameFromYuvFile() and ExtractFrameFromY4mFile(),
instad of the previous ExtractFrameFromI420(). The decision
as to which one to use is taken from the file extension,
if it is .y4m then is considered a YUV4MPEG file, otherwise
is taken as a raw .yuv file.

It also removes the pseudo duplicated function 
GetNextI420Frame(), that is used from psnr_ssim_analyzer.c,
and adds support for y4m files there.

Tested/validated via local compile-run.

YUV4MPEG is a trivial container with a file header
and a per-frame header, see [1]

[1]
http://wiki.multimedia.cx/index.php?title=YUV4MPEG2

BUG=https://code.google.com/p/chromium/issues/detail?id=343504



git-svn-id: http://webrtc.googlecode.com/svn/trunk@5702 4adac7df-926f-26a2-2b94-8c16560cd09d
Add support for YUV4MPEG file reading to tools files. (Minor fix).


git-svn-id: http://webrtc.googlecode.com/svn/trunk@5703 4adac7df-926f-26a2-2b94-8c16560cd09d