Bug 1319850 - part 1, Add MessagePumpForAndroidUI r=nfroyd

ipc/glue/MessagePump.cpp

@@ -463,3 +463,29 @@ MessagePumpForNonMainUIThreads::AfterProcessNextEvent(nsIThreadInternal *thread,
 }
 
 #endif // XP_WIN
+
+#if defined(MOZ_WIDGET_ANDROID)
+void
+MessagePumpForAndroidUI::Run(Delegate* delegate)
+{
+  MOZ_CRASH("MessagePumpForAndroidUI should never be Run.");
+}
+
+void
+MessagePumpForAndroidUI::Quit()
+{
+  MOZ_CRASH("MessagePumpForAndroidUI should never be Quit.");
+}
+
+void
+MessagePumpForAndroidUI::ScheduleWork()
+{
+  MOZ_CRASH("MessagePumpForAndroidUI should never ScheduleWork");
+}
+
+void
+MessagePumpForAndroidUI::ScheduleDelayedWork(const TimeTicks& delayed_work_time)
+{
+  MOZ_CRASH("MessagePumpForAndroidUI should never ScheduleDelayedWork");
+}
+#endif // defined(MOZ_WIDGET_ANDROID)

ipc/glue/MessagePump.h

@@ -164,6 +164,43 @@ private:
 };
 #endif // defined(XP_WIN)
 
+#if defined(MOZ_WIDGET_ANDROID)
+/*`
+ * The MessagePumpForAndroidUI exists to enable IPDL in the Android UI thread. The Android
+ * UI thread event loop is controlled by Android. This prevents running an existing
+ * MessagePump implementation in the Android UI thread. In order to enable IPDL on the
+ * Android UI thread it is necessary to have a non-looping MessagePump. This class enables
+ * forwarding of nsIRunnables from MessageLoop::PostTask_Helper to the registered
+ * nsIEventTarget with out the need to control the event loop. The only member function
+ * that should be invoked is GetXPCOMThread. All other member functions will invoke MOZ_CRASH
+*/
+class MessagePumpForAndroidUI : public base::MessagePump {
+
+public:
+  MessagePumpForAndroidUI(nsIEventTarget* aEventTarget)
+    : mEventTarget(aEventTarget)
+  { }
+
+  virtual void Run(Delegate* delegate);
+  virtual void Quit();
+  virtual void ScheduleWork();
+  virtual void ScheduleDelayedWork(const base::TimeTicks& delayed_work_time);
+  virtual nsIEventTarget* GetXPCOMThread()
+  {
+    return mEventTarget;
+  }
+
+private:
+  ~MessagePumpForAndroidUI()
+  { }
+  MessagePumpForAndroidUI()
+  { }
+
+  nsIEventTarget* mEventTarget;
+};
+#endif // defined(MOZ_WIDGET_ANDROID)
+
+
 } /* namespace ipc */
 } /* namespace mozilla */