Merge trunk r35030 to the 249 branch

Merge trunk r35030 to the 249 branch.

Adapt Chrome to use KeystoneRegistration 1.0.7.1306.  Use "tag path" and "tag
key" to direct Keystone to use a tag stored in the application as opposed to
in its ticket.

BUG=30730
TEST= - ksadmin --print-ticket --productid com.google.Chrome should show
        tagPath pointing to GC.app/Contents/Info.plist, and
        tagKey of KSChannelID;
      - ksadmin --print-tag --productid com.google.Chrome should show the
        value of the KSChannelID key in GC.app/Contents/Info.plist;
        this should be the tag that is used for autoupdates
     The above steps should be validated after the following operations:
      - launching Chrome when on a user ticket,
      - promoting Chrome from a user ticket to a system ticket, and
      - when a Chrome update is applied (using this version of
        keystone_install.sh) when on either a user or a system ticket.
     The tagPath and tagKey will NOT be set when launching Chrome on a
     system (promoted) ticket, but they WILL be set when the ticket is
     initially promoted and also when an update is applied using this version
     of keystone_install.sh.
Review URL: http://codereview.chromium.org/506061

TBR=mark@chromium.org

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=35031