Use the default dispatcher where possible for nested message loops.

Use the default dispatcher where possible for nested message loops.

Notable changes:
 * Add QuitNestedMessageLoop() to client::DispatcherClient, which can be used to
   terminate a nested loop started by RunWithDispatcher().
 * FirstRunDialog and SimpleMessageBoxViews are no longer
   MessagePumpDispatchers. The default dispatcher is used instead, and
   QuitNestedMessageLoop() is called to terminate the loop instead of returning
   POST_DISPATCH_QUIT_LOOP from the Dispatch() override.

BUG=none
R=sky@chromium.org

Previously committed in r253723, but reverted in r253744 because it broke
interactive_ui_tests on win-dbg.

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=254089

[sky, 2014-02-27 00:30:54]

LGTM

[sadrul, 2014-02-27 05:23:23]

Committed patchset #1 manually as r253723 (tree was closed).

[scottmg, 2014-02-27 07:45:47]

A revert of this CL has been created in
https://codereview.chromium.org/182753002/ by scottmg@chromium.org.

The reason for reverting is: win debug interactive_ui_tests:

BookmarkBarViewTest12.CloseWithModalDialog (run #1):
[ RUN      ] BookmarkBarViewTest12.CloseWithModalDialog
[3940:2156:0226/224958:2493504:FATAL:desktop_dispatcher_client.cc(33)] Check
failed: !quit_closure_.is_null(). .

[sadrul, 2014-02-27 22:19:55]

On 2014/02/27 07:45:47, scottmg wrote:
> A revert of this CL has been created in
> https://codereview.chromium.org/182753002/ by mailto:scottmg@chromium.org.
> 
> The reason for reverting is: win debug interactive_ui_tests:

Sorry about the breakage :-( (too bad the win-debug trybot does not run
interactive-ui-tests by default)

The reason for the crash was that I was terminating the nested-loop from the
wrong dispatcher-client. I have put up a fix for it in patchset 3, which is
passing the interactive-ui-tests in the win-debug trybot.

sky@ Do you mind taking another look at the fix? (the change is in
SimpleMessageBoxViews. The same fix is not needed for FirstRunDialog, since the
code always uses the dispatcher client of the dialog itself).

[sky, 2014-02-27 23:17:47]

LGTM

[sadrul, 2014-02-28 10:41:39]

Committed patchset #4 manually as r254089 (presubmit successful).