Unrevert 152017 - Add chrome.runtime.onStartup, which is fired on browser start.

Unrevert 152017 - Add chrome.runtime.onStartup, which is fired on browser start.

I reused LazyBackgroundTaskQueue so that this works for regular background
pages, which may not be fully loaded by the time this event is dispatched.

BUG=132328
Review URL: https://chromiumcodereview.appspot.com/10828218


Reason for revert: introduced a frequent crash


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=152238

[Matt Perry, 2012-08-17 23:37:30]

http://codereview.chromium.org/10855237/diff/1/chrome/browser/extensions/api/...
File chrome/browser/extensions/api/runtime/runtime_api.cc (right):

http://codereview.chromium.org/10855237/diff/1/chrome/browser/extensions/api/...
chrome/browser/extensions/api/runtime/runtime_api.cc:36: return;
This should fix the crash. We were crashing when the LazyBgTaskQueue executed
all the pending tasks for a destroyed bg page (host=NULL), which happens when
the profile manager is deleted. I can't find a good way to detect that the
profile manager is deleted, so I'm just going with this.

[Yoyo Zhou, 2012-08-18 00:02:42]

LGTM

[commit-bot: I haz the power, 2012-08-18 00:51:38]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/mpcomplete@chromium.org/10855237/1

[commit-bot: I haz the power, 2012-08-18 04:10:07]

Change committed as 152238