Make possible restarting extensions from the chrome://extensions/ page....

Make possible reloading extensions from the chrome://extensions/ page.

http://crbug.com/16459

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=21719

[Aaron Boodman, 2009-07-24 03:59:43]

There can be multiple ExtensionHosts for each extension process, so this code
isn't quite right as is. Also, there can be tabs that host extension content,
and this code won't find or restart those.

A better way to do this would be to actually unload and reload the extension.
You would add a ExtensionsService::ReloadExtension(id) method and it would:

a) Reload the extension (see the code for ReloadExtensions() for an example)
  - you will have to check if the extension's location is INTERNAL, in that case
you'll want to use code like LoadExtension() -- it is slightly different.

b) Send a notification out like EXTENSION_RELOADED

c) Classes throughout Chrome would listen to this notifiication to refresh their
extension-related code.

If you look for all the code that currently listens to EXTENSION_UNLOADED you
will find all the places you need to change to handle EXTENSION_RELOADED.

[Paweł Hajdan Jr., 2009-07-24 18:55:58]

Please take a look to see if I'm on the right path.

Currently when I kill for example the buildbot extension, it doesn't re-appear
after reload, even in the Task Manager.

However, when I click "reload" when it isn't crash, it (the extension) at least
doesn't disappear or crash.

[Aaron Boodman, 2009-07-24 19:09:34]

Looking better!

[Paweł Hajdan Jr., 2009-07-27 19:30:59]

Please review, I made sure it works now.

[Aaron Boodman, 2009-07-27 21:14:45]

lgtm with a nit

http://codereview.chromium.org/159323/diff/1028/14
File chrome/browser/extensions/extension_process_manager.h (right):

http://codereview.chromium.org/159323/diff/1028/14#newcode62
Line 62: ExtensionHost* GetExtensionHost(const std::string& extension_id);
This method is no longer used and should be removed.