Prepare status area to support multiple trays.

ash/shell/content_client/shell_browser_main_parts.cc

Index: ash/shell/content_client/shell_browser_main_parts.cc
diff --git a/ash/shell/content_client/shell_browser_main_parts.cc b/ash/shell/content_client/shell_browser_main_parts.cc
index 6913970b442cc31222dab43138d068a3f8d1b74d..5c82bdfbe666ea4465dbccebf2d5389878609f47 100644
--- a/ash/shell/content_client/shell_browser_main_parts.cc
+++ b/ash/shell/content_client/shell_browser_main_parts.cc
@@ -32,6 +32,10 @@
 #include "ui/base/touch/touch_factory.h"
 #endif
 
+#if defined(OS_CHROMEOS)
+#include "chromeos/dbus/dbus_thread_manager.h"
+#endif
+
 namespace ash {
 namespace shell {
 void InitWindowTypeLauncher();
@@ -74,6 +78,12 @@ void ShellBrowserMainParts::PreMainMessageLoopStart() {
 }
 #endif
 
+void ShellBrowserMainParts::PostMainMessageLoopStart() {
+#if defined(OS_CHROMEOS)
+  chromeos::DBusThreadManager::Initialize();
+#endif
+}
+
 void ShellBrowserMainParts::PreMainMessageLoopRun() {
   browser_context_.reset(new content::ShellBrowserContext);