Merge trunk r242964 to the 33.0.1750 branch.

Merge trunk r242964 and r243035 to the 33.0.1750 branch.

r242964:
> Expand the Keystone tag to contain the system's CPU's bitness and whether a
> full installer is desired.
>
> Formerly, the tag identified only the channel that Chrome was on. The tag is
> being enhanced to detect the CPU's bitness (adding "-32bit" for 32-bit-only,
> non-64-bit-capable CPUs) and whether a full (as opposed to binary diff patch)
> update is requested (adding "-full").
>
> CPU bitness detection ought to be a feature of Keystone, but Keystone uses the
> NXGetLocalArchInfo to determine the CPU type, and winds up always reporting
> "i486". The "-32bit" tag suffix will be present whenever the
> "hw.cpu64bit_capable" sysctl name is not found or has value 0. This enables
> proper detection of users who are capable of running 64-bit Chrome on the
> server side.
>
> When a binary diff patch update application fails in dirpatcher, typically the
> result of modifications made to existing installations, the "-full" tag suffix
> will be set. On a subsequent update attempt, the server can detect this value
> and provide the client with a full updater package, which does not depend on
> the existing installation. The "-full" tag suffix is cleared on successful
> update installation.
>
> BUG=18323, 54047, 225352, 303280, 316916
> R=thakis@chromium.org
>
> Review URL: https://codereview.chromium.org/102963007

r243035:
> Switch exit status from 77 (try again later) back to 12/13 (errors).
>
> When driving an update from KeystoneRegistration, Chrome sees 77 as success.
> This causes the about page to say that an update was successfully installed
> and offer the option to relaunch. When the user clicks Relaunch, Chrome quits
> and the same old version restarts and starts trying to apply an update again.
> This seems kind of glitchy.
>
> I'm switching back to the failure codes, because those are properly reported
> in the UI. In the future, I can make keystone_glue.mm check for the
> .want_full_installer file when update installation fails and silently retry
> installation once, for a seamless "error 12"-free experience.
>
> BUG=54047, 303280
> TBR=thakis
>
> Review URL: https://codereview.chromium.org/121673003

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=243102

[Mark Mentovai, 2014-01-06 16:59:09]

Committed patchset #2 manually as r243102.