Add MediaServiceThrottler

media/base/android/java/src/org/chromium/media/MediaServerCrashListener.java

Index: media/base/android/java/src/org/chromium/media/MediaServerCrashListener.java
diff --git a/media/base/android/java/src/org/chromium/media/MediaServerCrashListener.java b/media/base/android/java/src/org/chromium/media/MediaServerCrashListener.java
new file mode 100644
index 0000000000000000000000000000000000000000..9245980a77e812285296c15a97e96bd4113a55e8
--- /dev/null
+++ b/media/base/android/java/src/org/chromium/media/MediaServerCrashListener.java
@@ -0,0 +1,109 @@
+// 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.
+
+package org.chromium.media;
+
+import android.content.Context;
+import android.media.MediaPlayer;
+import android.os.SystemClock;
+
+import org.chromium.base.Log;
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.annotations.JNINamespace;
+import org.chromium.base.annotations.MainDex;
+import org.chromium.content.R;
+
+/**
+ * Class for listening to Android MediaServer crashes to throttle media decoding
+ * when needed.
+ */
+@MainDex
+@JNINamespace("media")
+public class MediaServerCrashListener implements MediaPlayer.OnErrorListener {
+    private static final String TAG = "crMediaCrashListener";
+    private static final long UNKNOWN_TIME = -1;
+
+    // Watchdog player. Used to listen to all media server crashes.
+    private MediaPlayer mPlayer;
+    private final Context mContext;
+
+    // Protecting the creation/release of the watchdog player.
+    private final Object mLock = new Object();
+
+    // Approximate time necessary for the MediaServer to restart after a crash.
+    private static final int APPROX_MEDIA_SERVER_RESTART_TIME_IN_MS = 5000;
+
+    // The last time we reported a failure to create the watchdog as a server crash.
+    private long mLastReportedWatchdogCreationFailure = UNKNOWN_TIME;
+
+    private long mNativeMediaServerCrashListener;
+
+    @CalledByNative
+    private static MediaServerCrashListener create(
+            Context context, long nativeMediaServerCrashListener) {
+        return new MediaServerCrashListener(context, nativeMediaServerCrashListener);
+    }
+
+    private MediaServerCrashListener(Context context, long nativeMediaServerCrashListener) {
+        mContext = context;
+        mNativeMediaServerCrashListener = nativeMediaServerCrashListener;
+    }
+
+    @CalledByNative
+    public void releaseWatchdog() {
+        if (mPlayer == null) return;
+
+        mPlayer.release();
+        mPlayer = null;
+    }
+
+    @CalledByNative
+    public boolean startListening() {
+        if (mPlayer != null) return true;
+
+        try {
+            mPlayer = MediaPlayer.create(mContext, R.raw.empty);
+        } catch (IllegalStateException e) {
+            Log.e(TAG, "Exception while creating the watchdog player.", e);
+        } catch (RuntimeException e) {
+            Log.e(TAG, "Exception while creating the watchdog player.", e);
+        }
+
+        if (mPlayer != null) {
+            mPlayer.setOnErrorListener(MediaServerCrashListener.this);
+
+            // Reset the reported creation failure time on successful
+            // watchdog creation.
+            mLastReportedWatchdogCreationFailure = UNKNOWN_TIME;
+            return true;
+        }
+
+        long currentTime = SystemClock.elapsedRealtime();
+
+        // It takes ~5s for the MediaServer to restart. Do not report a
+        // failure to create a watchdog MediaPlayer as a crash more than
+        // once per 5s, to prevent a burst of calls to startListening() from
+        // artificially inflating the number of crashes.
+        if (mLastReportedWatchdogCreationFailure == UNKNOWN_TIME
+                || (currentTime - mLastReportedWatchdogCreationFailure)
+                        > APPROX_MEDIA_SERVER_RESTART_TIME_IN_MS) {
+            Log.e(TAG, "Unable to create watchdog player, treating it as server crash.");
+            nativeOnMediaServerCrashDetected(mNativeMediaServerCrashListener, false);
+            mLastReportedWatchdogCreationFailure = currentTime;
+        }
+        return false;
+    }
+
+    @Override
+    public boolean onError(MediaPlayer mp, int what, int extra) {
+        if (what == MediaPlayer.MEDIA_ERROR_SERVER_DIED) {
+            nativeOnMediaServerCrashDetected(mNativeMediaServerCrashListener, true);
+            releaseWatchdog();
+        }
+        return true;
+    }
+
+    private native void nativeOnMediaServerCrashDetected(
+            long nativeMediaServerCrashListener, boolean watchdogNeedsRelease);
+}