Move InstallObserver::OnBeginExtensionInstall parameters to a struct

Move InstallObserver::OnBeginExtensionInstall parameters to a struct

The parameters of InstallObserver::OnBeginExtensionInstall() have been
moved to a struct to allow additional parameters to be added easily
without changing the signature of the function.

BUG=None
TEST=unit_tests, browser_tests

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=235681

[tmdiep, 2013-11-14 07:05:34]

The motivation behind this patch is so that I can add/remove an "is_ephemeral"
flag to the OnBeginExtensionInstall function easily.  In general, this will make
it easier to add other parameters to this notification in the future, especially
as most implementations of the function are empty anyway.

Please add additional reviewers, if necessary. Thanks.

[benwells, 2013-11-15 03:59:04]

lgtm

[commit-bot: I haz the power, 2013-11-17 22:17:03]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/tmdiep@chromium.org/72463002/1

[commit-bot: I haz the power, 2013-11-18 09:33:12]

Change committed as 235681