Don't forward declare RWLockWrapper in clock.h

Include rw_lock_wrapper.h instead of forward declaring. This is to
come around problems with thread annotations in some build systems.

BUG=3516
R=mflodman@webrtc.org, pbos@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/17809004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6545 4adac7df-926f-26a2-2b94-8c16560cd09d
Add Chromium's src/buildtools to DEPS.

GN for WebRTC was broken by the depot_tools change in
https://codereview.chromium.org/341533006/ that changes
the gn.py wrapper to use GN in src/buildtools instead of the
previous location in tools/gn/bin.

This buildtools repo was added for Chromium in
https://codereview.chromium.org/281863002 and the hooks were
updated in https://codereview.chromium.org/340153002

This adds the buildtools dir and updates our download hooks.

BUG=webrtc:3441
TEST=Locally running GN (trybots currently cannot handle DEPS changes properly)
R=niklas.enbom@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/15929004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6546 4adac7df-926f-26a2-2b94-8c16560cd09d
clock.h: Removed GUARDED_BY annotation as it breaks som builds.

BUG=N/A
TBR=henrik.lundin@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/14769004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6547 4adac7df-926f-26a2-2b94-8c16560cd09d
Receiver bit-exactness test for AudioCoding Module

This CL introduces a bit-exactness test for the receive-side of the
AudioCoding Module. The main part of the test is done in the helper
class AcmReceiveTest. The test is executed from the test fixture
AcmReceiverBitExactness.

The test inserts packets from a pre-encoded RTP file. The output is
summed up into a checksum, which is verified versus a reference at the
end of the test. Alternatively, if the flag --generate_output is given,
the output is written to a file for subjective verification.

R=kwiberg@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/13769004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6549 4adac7df-926f-26a2-2b94-8c16560cd09d