Move EventWrapper class to target video_coding_legacy.

And remove some unneeded logic for WEBRTC_EVENT_INFINITE.

Bug: webrtc:3380
Change-Id: Ibf632493edc6ced1609bd9ced44c2020fe9878cf
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/169846
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30700}

modules/video_coding/event_wrapper.h

@@ -0,0 +1,46 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef MODULES_VIDEO_CODING_EVENT_WRAPPER_H_
+#define MODULES_VIDEO_CODING_EVENT_WRAPPER_H_
+
+namespace webrtc {
+enum EventTypeWrapper { kEventSignaled = 1, kEventTimeout = 2 };
+
+class EventWrapper {
+ public:
+  // Factory method. Constructor disabled.
+  static EventWrapper* Create();
+
+  virtual ~EventWrapper() {}
+
+  // Releases threads who are calling Wait() and has started waiting. Please
+  // note that a thread calling Wait() will not start waiting immediately.
+  // assumptions to the contrary is a very common source of issues in
+  // multithreaded programming.
+  // Set is sticky in the sense that it will release at least one thread
+  // either immediately or some time in the future.
+  virtual bool Set() = 0;
+
+  // Puts the calling thread into a wait state. The thread may be released
+  // by a Set() call depending on if other threads are waiting and if so on
+  // timing. The thread that was released will reset the event before leaving
+  // preventing more threads from being released. If multiple threads
+  // are waiting for the same Set(), only one (random) thread is guaranteed to
+  // be released. It is possible that multiple (random) threads are released
+  // Depending on timing.
+  //
+  // |max_time_ms| is the maximum time to wait in milliseconds.
+  virtual EventTypeWrapper Wait(int max_time_ms) = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_VIDEO_CODING_EVENT_WRAPPER_H_