Reland: Refactor code that defers extension background page loading
src/extensions depends on chrome::NOTIFICATION_PROFILE_CREATED to support
deferred loading of extension background pages when the profile isn't ready
yet. This is a layering violation.
* Remove Chrome concepts like "browser window ready" and "profile created"
from ProcessManager. Introduce ProcessManagerDelegate with a general concept
of deferring background page loading.
* Consolidate all the tricky Chrome-specific background page loading rules into
ChromeProcessManagerDelegate. This keeps all the rules in one place. Annotate
each block of special case code with the bug that inspired it.
* Extend unit test coverage for ProcessManager.
This will make it easier to eliminate chrome::NOTIFICATION_PROFILE_DESTROYED
in ProcessManager in a later CL.
(Original CL https://codereview.chromium.org/
381283002 broke valgrind bots
because it was initializing left-over BrowserContextKeyedServices from tests
running earlier in the same process.)
BUG=392658
TEST=unit_tests ProcessManagerTest, browser_tests ProcessManagerBrowserTest, manual
Review URL: https://codereview.chromium.org/
408523005
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@284593 0039d316-1c4b-4281-b951-d872f2087c98