Add macros and APIs for webrtc histograms.

BUG=crbug/419657

Code that links system_wrappers.gyp:system_wrappers should either:
- provide implementations for the APIs, or
- link with default implementations in system_wrappers.gyp:system_wrappers_default.

R=andresp@webrtc.org, kjellander@webrtc.org, mflodman@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/22809004

git-svn-id: http://webrtc.googlecode.com/svn@7508 4adac7df-926f-26a2-2b94-8c16560cd09d
Adding file from test.webrtc.org domain to be downloaded

This has been configured to allow cross domain to access this generated
file:
https://test.webrtc.org/test-download-file/9000KB.data

R=andresp@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/25939004

git-svn-id: http://webrtc.googlecode.com/svn@7509 4adac7df-926f-26a2-2b94-8c16560cd09d
Adding three video conference bots test

A video conference between three bots, each bot creating two
peerConnections, and each peer connected to one of the other bots.

R=andresp@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/24099004

git-svn-id: http://webrtc.googlecode.com/svn@7510 4adac7df-926f-26a2-2b94-8c16560cd09d
Break out ComputeSnr function in ns_core

This is done in order to make the code more readible and maintainable.
The output is bit-exact.

BUG=webrtc:3811
R=bjornv@webrtc.org, kwiberg@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/31729004

git-svn-id: http://webrtc.googlecode.com/svn@7511 4adac7df-926f-26a2-2b94-8c16560cd09d
Break out FFT function in ns_core

This is done in order to make the code more readible and maintainable.
This introduces an error of only +1 and -1.

BUG=webrtc:3811
R=bjornv@webrtc.org, kwiberg@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/27749004

git-svn-id: http://webrtc.googlecode.com/svn@7512 4adac7df-926f-26a2-2b94-8c16560cd09d
Break out WebRtcNs_UpdateNoise function in ns_core

This is done in order to make the code more readible and maintainable.
It generates bit-exact output.

BUG=webrtc:3811
R=bjornv@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/25889004

git-svn-id: http://webrtc.googlecode.com/svn@7513 4adac7df-926f-26a2-2b94-8c16560cd09d
Break out WebRtcNs_ComputeDdUpdate function in ns_core

This is done in order to make the code more readible and maintainable.
It generates bit-exact output.

BUG=webrtc:3811
R=bjornv@webrtc.org, kwiberg@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/31739004

git-svn-id: http://webrtc.googlecode.com/svn@7514 4adac7df-926f-26a2-2b94-8c16560cd09d
(Auto)update libjingle 78344087-> 78381351

git-svn-id: http://webrtc.googlecode.com/svn@7515 4adac7df-926f-26a2-2b94-8c16560cd09d
(Auto)update libjingle 78381351-> 78389679

git-svn-id: http://webrtc.googlecode.com/svn@7516 4adac7df-926f-26a2-2b94-8c16560cd09d
patch from issue 25469004

git-svn-id: http://webrtc.googlecode.com/svn@7517 4adac7df-926f-26a2-2b94-8c16560cd09d