Revert 106142 - Add a new globals object for PPAPI tracking information.

Revert 106142 - Add a new globals object for PPAPI tracking information.

This adds a specialization on the host and plugin side of the proxy. This
replaces the ad-hoc singleton tracking done by the resource and var trackers
with just being getters on this global object.

Most code can use the single PpapiGlobals class. I also allow code to get the
host and plugin specializations since some code needs access to some specific
features of each side.

In a later pass I'll move the other stuff out of TrackerBase and delete it.

TEST=none
BUG=none

Review URL: http://codereview.chromium.org/8316008

TBR=brettw@chromium.org
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=106148