Common: Move the Event class to a separate file, and add tests for it. Fix includes everywhere to match this.

Source/UnitTests/Common/EventTest.cpp

@@ -0,0 +1,42 @@
+// Copyright 2014 Dolphin Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+#include <gtest/gtest.h>
+#include <thread>
+
+#include "Common/Event.h"
+
+using Common::Event;
+
+TEST(Event, MultiThreaded)
+{
+	Event has_sent, can_send;
+	int shared_obj;
+	const int ITERATIONS_COUNT = 100000;
+
+	auto sender = [&]() {
+		for (int i = 0; i < ITERATIONS_COUNT; ++i)
+		{
+			can_send.Wait();
+			shared_obj = i;
+			has_sent.Set();
+		}
+	};
+
+	auto receiver = [&]() {
+		for (int i = 0; i < ITERATIONS_COUNT; ++i) {
+			has_sent.Wait();
+			EXPECT_EQ(i, shared_obj);
+			can_send.Set();
+		}
+	};
+
+	std::thread sender_thread(sender);
+	std::thread receiver_thread(receiver);
+
+	can_send.Set();
+
+	sender_thread.join();
+	receiver_thread.join();
+}