Make extensions developer mode warning controllable by experiments

chrome/browser/ui/extensions/extension_message_bubble_factory.cc

Index: chrome/browser/ui/extensions/extension_message_bubble_factory.cc
diff --git a/chrome/browser/ui/extensions/extension_message_bubble_factory.cc b/chrome/browser/ui/extensions/extension_message_bubble_factory.cc
index b4a67c183501b2aad73be436984849385bf32baa..387cab9ad1225e934d8f71ba4d493a96a5e62501 100644
--- a/chrome/browser/ui/extensions/extension_message_bubble_factory.cc
+++ b/chrome/browser/ui/extensions/extension_message_bubble_factory.cc
@@ -21,9 +21,9 @@ namespace {
 base::LazyInstance<std::set<Profile*> > g_profiles_evaluated =
     LAZY_INSTANCE_INITIALIZER;
 
-// Currently, we only show these bubbles on windows platforms. This can be
+// Currently, we only show these bubbles on windows and mac. This can be
 // overridden for testing purposes.
-#if defined(OS_WIN)
+#if defined(OS_WIN) || defined(OS_MACOSX)

[Devlin, 2015/05/06 21:21:32]

This will enable all of these bubbles, not just the dev mode warning one.

I wonder if it would be better to have a centralized experiment for all of them,
since I think we're discussing having them all on mac anyway.  But I'm not sure
how that would work with turning on a subset.

[asargent_no_longer_on_chrome, 2015/05/06 23:41:24]

Jake and I touched base today and I mentioned this, and his take was that this
was ok.

We definitely want the SuspiciousExtensionBubbleController turned on, because
that's important UI for the webstore lockdown (it's what tells you about any
non-webstore extensions that have been disabled). The settings API is currently
only available on windows, so for now that bubble can't display for mac, but if
we bring the API to mac (I suggested to Jake that we should consider doing that
in the near future), we'd probably want the same warnings as windows. That just
leaves the proxy override warning one, and the same reasoning applies to mac as
windows for why we'd want to warn users. 

Does this seem sufficient to you for us to move forward? Or should we start an
email thread with Jake to discuss further? 

[Devlin, 2015/05/06 23:51:56]

In principle, I'm fine with launching all of these.  But I do think it's a
little weird that we put the dev mode behind an experiment, but just turn on the
others to 100% - especially since the suspicious bubble controller's incarnation
on mac hasn't gone through launch/UI review, AFAIK.

Could we put them all in one user-protection-bubble experiment?  Then we could
dial it up when we're sure they're ready?

Also, IIRC, I tested out the suspicious bubble on mac, and it *mostly* worked,
but there was a line or two I had to change.  I might have done that as part of
a separate CL, but I'm not 100% sure - I can check tomorrow if there are any
changes that need to happen in that respect.

[Devlin, 2015/05/07 15:44:17]

Just confirmed that the suspicious bubble does WAI.  Still have the same
concerns re launch/ui review, but at least I'm pretty sure this won't cause epic
crashes. :)

 bool g_enabled = true;
 #else
 bool g_enabled = false;