Changes to reinitialize the appcache system if/when DiskCache initialization fails.

Older versions would attempt to delete the existing data on disk, and disable the appcache system until browser restart, and then have a clean slate. With these changes, we no longer wait for a browser restart get going again. Also fixes a bug with the older behavior, it was racy and could *fail* to delete the old data.

BUG=258191,95101

Review URL: https://codereview.chromium.org/25955002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229540 0039d316-1c4b-4281-b951-d872f2087c98
Set Instant support to true in ChromeViewHostMsg_LogEvent IPC message handler.

Follow up of crrev.com/26317007.

BUG=272583
TEST=none

Review URL: https://codereview.chromium.org/26124005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229541 0039d316-1c4b-4281-b951-d872f2087c98
Add -b build option to update_reference build.

Adding an option to download chrome official builds from gs:// using
build numbers.

BUG=302065

Review URL: https://codereview.chromium.org/26135006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229542 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229541
SVN changes up to revision 229542