Disk cache: Make sure that we don't use the address of an entry before we see if it is valid.
Disk cache: Make sure that we don't use the address of an
entry before we see if it is valid.

BUG=96355
TEST=none
Review URL: http://codereview.chromium.org/7875010

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@100931 0039d316-1c4b-4281-b951-d872f2087c98

adobe/chromium,adobe/chromium,yitian134/chromium,gavinp/chromium,gavinp/chromium,gavinp/chromium,adobe/chromium,gavinp/chromium,adobe/chromium,adobe/chromium,adobe/chromium,ropik/chromium,adobe/chromium,gavinp/chromium,ropik/chromium,yitian134/chromium,gavinp/chromium,yitian134/chromium,adobe/chromium,ropik/chromium,yitian134/chromium,yitian134/chromium,gavinp/chromium,ropik/chromium,ropik/chromium,gavinp/chromium,adobe/chromium,gavinp/chromium,yitian134/chromium,yitian134/chromium,ropik/chromium,ropik/chromium,ropik/chromium,adobe/chromium,yitian134/chromium,yitian134/chromium,adobe/chromium,ropik/chromium,yitian134/chromium,gavinp/chromium