[Resource Timing] Fix potential double free problem

  Currently, ResourceTimingInfoMap in ResourceFetcher releases a 
ResourceTimingInfo after a resource is reported.
  If when blink is in reporting a resource entry, which lead to buffer full and 
immediately invoke "window.stop()" as callback, it will dive into 
ResourceFetcher::didLoadResource again, and release the memory in a nested. 
After that,the outer double free the memory as it just report the entry.
  This patch remove ResourceTiming from map ealier and prevent the double free case.

Contributed by lifeasageek@gmail.com and pan.deng@intel.com

BUG=286414

Review URL: https://chromiumcodereview.appspot.com/23498018

git-svn-id: svn://svn.chromium.org/blink/trunk@157760 bbb929c8-8fbe-4397-9dbb-9b2b20218538