Reland: Fall back to X11 system tray icons if libappindicator is not available.

Reland: Fall back to X11 system tray icons if libappindicator is not available.

This CL also splits out the code wrt to handling the GTK menu for the app indicator icon out of app_indicator_icon.cc in order to share code with gtk2_status_icon.cc

BUG=267195
TEST=Manual, see steps below.
1) Run chrome in a system which does not have libappindicator
2) Generate HTML 5 notifications via https://developer.cdn.mozilla.net/media/uploads/demos/e/l/elfoxero/c17223c414d8ddafb7808972b5617d9e/html5-notifications_1400214081_demo_package/index.html
3) Ensure that the bell icon shows up in the system tray and that clicking on the bell icon brings up the message center

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=273999

[pkotwicz, 2014-05-30 17:39:04]

Elliot, can you please take a look?

Patch set #1 contains the CL as it landed in
https://codereview.chromium.org/291893009

Many thanks to earthdok@ for help with investigating the memory leak

app_indicator_set_menu() leaks memory. However, I have not been able to come up
with an appropriate suppression. Thankfully app_indicator_set_menu() should not
get hit in tests

https://codereview.chromium.org/306063003/diff/40001/chrome/browser/ui/libgtk...
File chrome/browser/ui/libgtk2ui/app_indicator_icon_menu.cc (right):

https://codereview.chromium.org/306063003/diff/40001/chrome/browser/ui/libgtk...
chrome/browser/ui/libgtk2ui/app_indicator_icon_menu.cc:25:
g_object_ref_sink(gtk_menu_);
I do not use OwnedWidgetGtk because app_indicator_set_menu() leaks memory and
the reference count of GtkMenu is not 1 at the time that the destructor is
called.

(Yes, I tried refactoring AppIndicatorIcon::SetMenu() so that
app_indicator_set_menu() with the new GtkMenu is called before the old
AppIndicatorIconMenu is destroyed)

[pkotwicz, 2014-05-30 17:39:06]

Elliot, can you please take a look?

Patch set #1 contains the CL as it landed in
https://codereview.chromium.org/291893009

Many thanks to earthdok@ for help with investigating the memory leak

app_indicator_set_menu() leaks memory. However, I have not been able to come up
with an appropriate suppression. Thankfully app_indicator_set_menu() should not
get hit in tests

[Elliot Glaysher, 2014-05-30 17:40:58]

lgtm

[pkotwicz, 2014-05-30 17:43:39]

The CQ bit was checked by pkotwicz@chromium.org

[commit-bot: I haz the power, 2014-05-30 17:46:53]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/pkotwicz@chromium.org/306063003/40001

[commit-bot: I haz the power, 2014-05-31 02:05:09]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  android_dbg_triggered_tests on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/android_dbg_triggered...)

[commit-bot: I haz the power, 2014-05-31 03:52:45]

Change committed as 273999