Fix deadlock during player shutdown when a Seek() and an Abort() are racing.
Fix deadlock during player shutdown when a Seek() and an Abort() are racing.

BUG=74031
TEST=trybots, repro site from bug report, and a layouttest which I probably won't be able to submit since it requires a large (14MB) video file to repro, and webkit's bugzilla assplodes on patches over 10MB.

Review URL: http://codereview.chromium.org/6690065

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@80163 0039d316-1c4b-4281-b951-d872f2087c98

gavinp/chromium,gavinp/chromium,adobe/chromium,adobe/chromium,ropik/chromium,adobe/chromium,yitian134/chromium,gavinp/chromium,gavinp/chromium,ropik/chromium,yitian134/chromium,adobe/chromium,yitian134/chromium,ropik/chromium,gavinp/chromium,Crystalnix/house-of-life-chromium,gavinp/chromium,Crystalnix/house-of-life-chromium,yitian134/chromium,ropik/chromium,adobe/chromium,ropik/chromium,ropik/chromium,adobe/chromium,Crystalnix/house-of-life-chromium,ropik/chromium,Crystalnix/house-of-life-chromium,Crystalnix/house-of-life-chromium,Crystalnix/house-of-life-chromium,Crystalnix/house-of-life-chromium,Crystalnix/house-of-life-chromium,yitian134/chromium,ropik/chromium,gavinp/chromium,adobe/chromium,yitian134/chromium,yitian134/chromium,yitian134/chromium,Crystalnix/house-of-life-chromium,adobe/chromium,ropik/chromium,gavinp/chromium,gavinp/chromium,adobe/chromium,yitian134/chromium,Crystalnix/house-of-life-chromium,adobe/chromium,Crystalnix/house-of-life-chromium,gavinp/chromium,adobe/chromium,yitian134/chromium