Remove MediaThrottler and MediaThrottleInfoBar

content/public/android/java/src/org/chromium/content/browser/MediaThrottler.java

Index: content/public/android/java/src/org/chromium/content/browser/MediaThrottler.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/MediaThrottler.java b/content/public/android/java/src/org/chromium/content/browser/MediaThrottler.java
deleted file mode 100644
index ece07e1c9eba85283f6f6bdcbd09e140d6bfa4b3..0000000000000000000000000000000000000000
--- a/content/public/android/java/src/org/chromium/content/browser/MediaThrottler.java
+++ /dev/null
@@ -1,224 +0,0 @@
-// 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.
-
-package org.chromium.content.browser;
-
-import android.content.Context;
-import android.media.MediaPlayer;
-import android.os.AsyncTask;
-import android.os.Handler;
-import android.os.Looper;
-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.metrics.RecordHistogram;
-import org.chromium.content.R;
-
-/**
- * Class for listening to Android MediaServer Crashes to throttle media decoding
- * when needed.
- */
-@JNINamespace("content")
-class MediaThrottler implements MediaPlayer.OnErrorListener {
-    private static final String TAG = "cr_MediaThrottler";
-    private static final long UNKNOWN_LAST_SERVER_CRASH_TIME = -1;
-
-    // Number of active decode requests.
-    private int mRequestCount;
-
-    // Application context.
-    private final Context mContext;
-
-    // Watch dog player. Used to listen to all media server crashes.
-    private MediaPlayer mPlayer;
-
-    // The last media server crash time since Chrome lauches.
-    private long mLastCrashTime = UNKNOWN_LAST_SERVER_CRASH_TIME;
-
-    // Server crash count since last reset() call.
-    private int mServerCrashCount;
-
-    // Object for synchronized access to memeber variables.
-    private final Object mLock = new Object();
-
-    // Handler for posting delayed tasks.
-    private Handler mHandler;
-
-    // Intervals between media server crashes that are considered normal. It
-    // takes about 5 seconds to restart the media server. So this value has to
-    // be larger than 5 seconds.
-    private static final long SERVER_CRASH_INTERVAL_THRESHOLD_IN_MILLIS = 60000;
-
-    // Delay to keep the watch dog player alive When there are no decoding
-    // requests. This is introduced to avoid recreating the watch dog over and
-    // over if a burst of small decoding requests arrive.
-    private static final int RELEASE_WATCH_DOG_PLAYER_DELAY_IN_MILLIS = 5000;
-
-    // When |mServerCrashCount| reaches this threshold, throttling will start.
-    // This is to prevent a page from loading a malformed video over and over
-    // to crash the media server excessively.
-    private static final int SERVER_CRASH_COUNT_THRESHOLD_FOR_THROTTLING = 4;
-
-    /**
-     * A background task to release the watch dog player.
-     */
-    private class ReleaseWatchDogTask extends AsyncTask<Void, Void, Void> {
-        @Override
-        protected Void doInBackground(Void... voids) {
-            synchronized (mLock) {
-                if (mRequestCount == 0 && mPlayer != null) {
-                    mPlayer.release();
-                    mPlayer = null;
-                }
-            }
-            return null;
-        }
-    }
-
-    private final Runnable mDelayedReleaseRunnable = new Runnable() {
-        @Override
-        public void run() {
-            new ReleaseWatchDogTask().execute();
-        }
-    };
-
-    @CalledByNative
-    private static MediaThrottler create(Context context) {
-        return new MediaThrottler(context);
-    }
-
-    private MediaThrottler(Context context) {
-        mContext = context;
-        mHandler = new Handler(Looper.getMainLooper());
-    }
-
-    /**
-     * A background task to start the watch dog player.
-     */
-    private class StartWatchDogTask extends AsyncTask<Void, Void, Void> {
-        @Override
-        protected Void doInBackground(Void... voids) {
-            synchronized (mLock) {
-                if (mPlayer != null || mRequestCount == 0) return null;
-                try {
-                    mPlayer = MediaPlayer.create(mContext, R.raw.empty);
-                } catch (IllegalStateException e) {
-                    Log.e(TAG, "Exception happens while creating the watch dog player.", e);
-                } catch (RuntimeException e) {
-                    Log.e(TAG, "Exception happens while creating the watch dog player.", e);
-                }
-                if (mPlayer == null) {
-                    Log.e(TAG, "Unable to create watch dog player, treat it as server crash.");
-                    onMediaServerCrash();
-                } else {
-                    mPlayer.setOnErrorListener(MediaThrottler.this);
-                }
-            }
-            return null;
-        }
-    }
-
-    /**
-     * Called to request the permission to decode media data.
-     *
-     * @return true if the request is permitted, or false otherwise.
-     */
-    @CalledByNative
-    private boolean requestDecoderResources() {
-        synchronized (mLock) {
-            long currentTime = SystemClock.elapsedRealtime();
-            if (mLastCrashTime != UNKNOWN_LAST_SERVER_CRASH_TIME
-                    && (currentTime - mLastCrashTime < SERVER_CRASH_INTERVAL_THRESHOLD_IN_MILLIS)
-                    && mServerCrashCount >= SERVER_CRASH_COUNT_THRESHOLD_FOR_THROTTLING) {
-                Log.e(TAG, "Request to decode media data denied due to throttling.");
-                return false;
-            }
-            mRequestCount++;
-            if (mRequestCount == 1 || mPlayer == null) {
-                mHandler.removeCallbacks(mDelayedReleaseRunnable);
-                mHandler.post(new Runnable() {
-                    @Override
-                    public void run() {
-                        new StartWatchDogTask().execute();
-                    }
-                });
-            }
-        }
-        return true;
-    }
-
-    /**
-     * Called to signal that a decode request has been completed.
-     */
-    @CalledByNative
-    private void onDecodeRequestFinished() {
-        synchronized (mLock) {
-            mRequestCount--;
-            if (mRequestCount == 0) {
-                // Don't release the watch dog immediately, there could be a
-                // number of small requests coming together.
-                prepareToStopWatchDog();
-            }
-        }
-    }
-
-    /**
-     * Posts a delayed task to stop the watch dog player.
-     */
-    private void prepareToStopWatchDog() {
-        mHandler.postDelayed(mDelayedReleaseRunnable, RELEASE_WATCH_DOG_PLAYER_DELAY_IN_MILLIS);
-    }
-
-    @Override
-    public boolean onError(MediaPlayer mp, int what, int extra) {
-        if (what == MediaPlayer.MEDIA_ERROR_SERVER_DIED) {
-            synchronized (mLock) {
-                onMediaServerCrash();
-            }
-        }
-        return true;
-    }
-
-    /**
-     * Called when media server crashes.
-     */
-    private void onMediaServerCrash() {
-        assert Thread.holdsLock(mLock);
-        long currentTime = SystemClock.elapsedRealtime();
-        if (mLastCrashTime != UNKNOWN_LAST_SERVER_CRASH_TIME
-                && (currentTime - mLastCrashTime < SERVER_CRASH_INTERVAL_THRESHOLD_IN_MILLIS)) {
-            mServerCrashCount++;
-        } else {
-            recordNumMediaServerCrashes();
-            mServerCrashCount = 1;
-        }
-        mLastCrashTime = currentTime;
-    }
-
-    /**
-     * Resets the MediaThrottler to its initial state so that subsequent requests
-     * will not be throttled.
-     */
-    @CalledByNative
-    private void reset() {
-        synchronized (mLock) {
-            recordNumMediaServerCrashes();
-            mServerCrashCount = 0;
-            mLastCrashTime = UNKNOWN_LAST_SERVER_CRASH_TIME;
-        }
-    }
-
-    /**
-     * Records the number of consecutive media server crashes in UMA.
-     */
-    private void recordNumMediaServerCrashes() {
-        assert Thread.holdsLock(mLock);
-        if (mServerCrashCount > 0) {
-            RecordHistogram.recordCountHistogram(
-                    "Media.Android.NumMediaServerCrashes", mServerCrashCount);
-        }
-    }
-}