Revert of Revert of Propagate audible state from player to the containing tab"

content/browser/media/audio_state_provider.cc

Index: content/browser/media/audio_state_provider.cc
diff --git a/content/browser/media/audio_state_provider.cc b/content/browser/media/audio_state_provider.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e09356a561f00cb43a524549eede96ea7c8caf2e
--- /dev/null
+++ b/content/browser/media/audio_state_provider.cc
@@ -0,0 +1,30 @@
+// Copyright 2015 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/browser/media/audio_state_provider.h"
+
+#include "base/logging.h"
+#include "content/browser/media/audio_stream_monitor.h"
+#include "content/public/browser/web_contents.h"
+
+namespace content {
+
+AudioStateProvider::AudioStateProvider(WebContents* contents)
+    : web_contents_(contents),
+      was_recently_audible_(false) {
+  DCHECK(web_contents_);
+}
+
+bool AudioStateProvider::WasRecentlyAudible() const {
+  return was_recently_audible_;
+}
+
+void AudioStateProvider::Notify(bool new_state) {
+  if (was_recently_audible_ != new_state) {
+    was_recently_audible_ = new_state;
+    web_contents_->NotifyNavigationStateChanged(INVALIDATE_TYPE_TAB);
+  }
+}
+
+} // namespace content