Always use libappindicator if available

This is in effect a temporary fix to always use libappindicator (when
available, but we have deb/rpm dependency on the lib, so it should
always be available), whilst I fix the dependency issue we have on the
build bots which would allow me to add a hard dependency and clean up
the code.

Bug: 799144, 797332 , 419673
Change-Id: Id64a452029b00ec8d86f0d35d319bebcfd8bf99e
Reviewed-on: https://chromium-review.googlesource.com/939732Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
Commit-Queue: Tim Brown <timbrown@chromium.org>
Cr-Commit-Position: refs/heads/master@{#539852}

chrome/browser/ui/libgtkui/app_indicator_icon.cc

@@ -82,34 +82,12 @@ app_indicator_set_icon_full_func app_indicator_set_icon_full = nullptr;
 app_indicator_set_icon_theme_path_func app_indicator_set_icon_theme_path =
     nullptr;
 
-bool ShouldUseLibAppIndicator() {
-  // Only use libappindicator where it is needed to support dbus based status
-  // icons. In particular, libappindicator does not support a click action.
-  std::unique_ptr<base::Environment> env(base::Environment::Create());
-  switch (base::nix::GetDesktopEnvironment(env.get())) {
-    case base::nix::DESKTOP_ENVIRONMENT_KDE4:
-    case base::nix::DESKTOP_ENVIRONMENT_KDE5:
-    case base::nix::DESKTOP_ENVIRONMENT_PANTHEON:
-    case base::nix::DESKTOP_ENVIRONMENT_UNITY:
-      return true;
-    case base::nix::DESKTOP_ENVIRONMENT_CINNAMON:
-    case base::nix::DESKTOP_ENVIRONMENT_GNOME:
-    case base::nix::DESKTOP_ENVIRONMENT_KDE3:
-    case base::nix::DESKTOP_ENVIRONMENT_OTHER:
-    case base::nix::DESKTOP_ENVIRONMENT_XFCE:
-      return false;
-  }
-}
-
 void EnsureMethodsLoaded() {
   if (g_attempted_load)
     return;
 
   g_attempted_load = true;
 
-  if (!ShouldUseLibAppIndicator())
-    return;
-
   void* indicator_lib = nullptr;
 
   // These include guards might be unnecessary, but let's keep them as a