Generate IDs for --load-extension by hashing the path instead
of incrementing a static counter.

BUG=21281
TEST=Load an unpacked extension from chrome://extensions/ that
does not have an ID in its manifest. The resulting ID should
be random-looking, not something like "aaaaaa".

Review URL: http://codereview.chromium.org/256049

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@28095 0039d316-1c4b-4281-b951-d872f2087c98
11 files changed