Revert 246905 "Revert 246894 "Wire up AGC to the MediaStreamAudi..."

The CL looks irrelevant to the failure since the http://build.chromium.org/p/chromium.linux/builders/Android%20Tests%20%28dbg%29/builds/18060 passes the build.

> Revert 246894 "Wire up AGC to the MediaStreamAudioProcessor."
> 
> It seems to have broken this test:
> [----------] 1 test from AudioStreamHandlerTest
> [ RUN      ] AudioStreamHandlerTest.ConsecutivePlayRequests
> ../../media/base/android/media_source_player_unittest.cc:1665: Failure
> Expected: (first_job) != (second_job), actual: 0x766d4210 vs 0x766d4210
> [  FAILED  ] MediaSourcePlayerTest.VideoConfigChangeContinuesAcrossSeek (125 ms)
> [ RUN      ] MediaSourcePlayerTest.SeekToThenReleaseThenStart
> [       OK ] MediaSourcePlayerTest.SeekToThenReleaseThenStart (82 ms)
> [----------] 8 tests from MediaSourcePlayerTest (590 ms total)
> 
> > Wire up AGC to the MediaStreamAudioProcessor.
> > 
> > This CL enables the AGC in the processor based on the constraints, and also trigger SetVolume() in the capturer if the AGC tries to adjust the volume.
> > 
> > There are also some small changes in the MediaStreamAudioProcessor and its unittest.
> > 
> > BUG=264611
> > TEST= content_unittest --gtest_filter="*MediaStreamAudioProcessor*"
> > 
> > Review URL: https://codereview.chromium.org/141513006
> 
> TBR=xians@chromium.org
> 
> Review URL: https://codereview.chromium.org/146923002

TBR=mad@chromium.org

Review URL: https://codereview.chromium.org/148213002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247208 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247208