Plumb a Browser->GPU surface destruction message for Android VDAs

content/common/gpu/media/avda_surface_tracker.cc

Index: content/common/gpu/media/avda_surface_tracker.cc
diff --git a/content/common/gpu/media/avda_surface_tracker.cc b/content/common/gpu/media/avda_surface_tracker.cc
new file mode 100644
index 0000000000000000000000000000000000000000..fbc49ea48ac128eea5ae764ef01174b246fe1f58
--- /dev/null
+++ b/content/common/gpu/media/avda_surface_tracker.cc
@@ -0,0 +1,49 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/common/gpu/media/avda_surface_tracker.h"
+
+#include "base/callback.h"
+#include "base/lazy_instance.h"
+#include "base/threading/thread_checker.h"
+
+namespace content {
+
+namespace {
+static base::LazyInstance<AVDASurfaceTracker> g_lazy_instance =
+    LAZY_INSTANCE_INITIALIZER;
+}
+
+AVDASurfaceTracker::AVDASurfaceTracker() {}
+
+AVDASurfaceTracker::~AVDASurfaceTracker() {}
+
+void AVDASurfaceTracker::RegisterOnDestroyingSurfaceCallback(
+    const OnDestroyingSurfaceCallback& cb) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  callbacks_.push_back(cb);
+}
+
+void AVDASurfaceTracker::UnregisterOnDestroyingSurfaceCallback(
+    const OnDestroyingSurfaceCallback& cb) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  for (auto it = callbacks_.begin(); it != callbacks_.end(); ++it) {
+    if (it->Equals(cb)) {
+      callbacks_.erase(it);
+      return;
+    }
+  }
+}
+
+void AVDASurfaceTracker::NotifyDestroyingSurface(int surface_id) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  for (const auto& cb : callbacks_)
+    cb.Run(surface_id);
+}
+
+AVDASurfaceTracker* AVDASurfaceTracker::GetInstance() {
+  return g_lazy_instance.Pointer();
+}
+
+}  // namespace content