Fix TracingController to properly track response callbacks when a TraceMessageFilter is removed before a response is received from the associated subprocess.

BUG=329003
TEST=none

Review URL: https://codereview.chromium.org/107103008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242806 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242806
All WebRTC content browsertests will now force iSAC 16K on Android.

R=wjia@chromium.org
BUG=181069

Review URL: https://codereview.chromium.org/118163002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242807 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242807