Upstream Chrome for Android Cast.

chrome/android/java/src/org/chromium/chrome/browser/media/remote/LockScreenTransportControl.java

Index: chrome/android/java/src/org/chromium/chrome/browser/media/remote/LockScreenTransportControl.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/media/remote/LockScreenTransportControl.java b/chrome/android/java/src/org/chromium/chrome/browser/media/remote/LockScreenTransportControl.java
new file mode 100644
index 0000000000000000000000000000000000000000..04488c3c5a2babde7a4470009d77be682ad452f9
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/media/remote/LockScreenTransportControl.java
@@ -0,0 +1,177 @@
+// Copyright 2014 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.chrome.browser.media.remote;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.util.Log;
+import android.view.KeyEvent;
+
+import org.chromium.base.CommandLine;
+import org.chromium.base.VisibleForTesting;
+import org.chromium.chrome.ChromeSwitches;
+import org.chromium.chrome.browser.media.remote.RemoteVideoInfo.PlayerState;
+
+import java.util.Set;
+
+import javax.annotation.Nullable;
+
+/**
+ * An abstract base class and factory for {@link TransportControl}s that are displayed on the lock
+ * screen.
+ */
+public abstract class LockScreenTransportControl
+        extends TransportControl implements MediaRouteController.UiListener {
+    private static final String TAG = "LockScreenTransportControl";
+
+    private static LockScreenTransportControl sInstance;
+
+    private MediaRouteController mMediaRouteController = null;
+
+    private static final Object LOCK = new Object();
+
+    private static boolean sDebug;
+
+    // Needed to get round findbugs complaints.

[Bernhard Bauer, 2015/03/13 12:18:02]

Nit: "around"

[aberent, 2015/03/13 19:04:35]

Done. Actually both are correct English, and "get round" is possibly more
correct in British English (if you are interested see, for example
http://separatedbyacommonlanguage.blogspot.co.uk/2007/05/round-and-around.html),
but changed since I think we use "get around" more often in Google.

+    private static void setSDebug() {
+        sDebug = CommandLine.getInstance().hasSwitch(ChromeSwitches.ENABLE_CAST_DEBUG_LOGS);
+    }
+
+    public LockScreenTransportControl() {
+        setSDebug();
+    }
+
+    /**
+     * {@link BroadcastReceiver} that receives the media button events from the lock screen and
+     * forwards the messages on to the {@link TransportControl}'s listeners.
+     *
+     *  Ideally this class should be private, but public is required to create as a
+     * BroadcastReceiver.
+     */
+    public static class MediaButtonIntentReceiver extends BroadcastReceiver {
+        @Override
+        public void onReceive(Context context, Intent intent) {
+            if (sDebug) Log.d(TAG, "Received intent: " + intent);
+            if (Intent.ACTION_MEDIA_BUTTON.equals(intent.getAction())) {
+                KeyEvent event = (KeyEvent) intent.getParcelableExtra(Intent.EXTRA_KEY_EVENT);
+                LockScreenTransportControl control = LockScreenTransportControl.getIfExists();
+                if (control == null) {
+                    Log.w(TAG, "Event received when no LockScreenTransportControl exists");
+                    return;
+                }
+                Set<Listener> listeners = control.getListeners();
+
+                // Ignore ACTION_DOWN. We'll get an ACTION_UP soon enough!
+                if (event.getAction() == KeyEvent.ACTION_DOWN) return;
+
+                switch (event.getKeyCode()) {
+                    case KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE:
+                        for (Listener listener : listeners) {
+                            if (control.isPlaying()) {
+                                listener.onPause();
+                            } else {
+                                listener.onPlay();
+                            }
+                        }
+                        break;
+                    case KeyEvent.KEYCODE_MEDIA_STOP:
+                        for (Listener listener : listeners)
+                            listener.onStop();
+                        break;
+                    default:
+                        Log.w(TAG, "Unrecognized event: " + event);
+                }
+            }
+        }
+    }
+
+
+    /**
+     * @return a {@code LockScreenTransportControl} based on the platform's SDK API or null if the
+     *         current platform's SDK API is not supported.
+     */
+    public static LockScreenTransportControl getOrCreate(Context context,
+            @Nullable MediaRouteController mediaRouteController) {
+        Log.d(TAG, "getOrCreate called");
+        synchronized (LOCK) {
+            if (sInstance == null) {
+
+                // TODO(aberent) Once the Android L SDK is formally released we should disable the
+                // lock screen for L onwards. On L the lock screen is replaced by lock screen
+                // notifications.

[Bernhard Bauer, 2015/03/13 12:18:02]

Yes, we should. :)

[aberent, 2015/03/13 19:04:35]

I have updated the comment to explain why we can't; at least without further
investigation.

+                if (!enabled()) {
+                    return null;
+                } else if (android.os.Build.VERSION.SDK_INT < 16) {
+                    sInstance = new LockScreenTransportControlV14(context);
+                } else if (android.os.Build.VERSION.SDK_INT < 18) {
+                    sInstance = new LockScreenTransportControlV16(context);
+                } else {
+                    sInstance = new LockScreenTransportControlV18(context);
+                }
+            }
+            sInstance.setVideoInfo(
+                    new RemoteVideoInfo(null, 0, RemoteVideoInfo.PlayerState.STOPPED, 0, null));
+
+            sInstance.mMediaRouteController = mediaRouteController;
+            return sInstance;
+        }
+    }
+
+    protected MediaRouteController getMediaRouteController() {
+        return mMediaRouteController;
+    }
+
+    /**
+     * TODO(aberent) From PlayMovies code. Either remove this and get V14/15 working or combine V14
+     * and V16 versions only and change getOrCreate to only support V16 or later.
+     *
+     * @return true if lock screen transport controls should be used on this device.
+     */
+    private static boolean enabled() {
+        // Lock screen controls don't work well prior to JB, see b/9101584
+        return android.os.Build.VERSION.SDK_INT >= 16;
+    }
+
+    /**
+     * Internal function for callbacks that need to get the current lock screen statically, but
+     * don't want to create a new one.
+     *
+     * @return the current lock screen, if any.
+     */
+    @VisibleForTesting
+    static LockScreenTransportControl getIfExists() {
+        return sInstance;
+    }
+
+    @Override
+    public void hide() {
+        onLockScreenPlaybackStateChanged(null, PlayerState.STOPPED);
+        mMediaRouteController.removeUiListener(this);
+    }
+
+    @Override
+    public void show(PlayerState initialState) {
+        mMediaRouteController.addUiListener(this);
+        onLockScreenPlaybackStateChanged(null, initialState);
+    }
+
+    @Override
+    public void setRouteController(MediaRouteController controller) {
+        synchronized (LOCK) {
+            if (sInstance != null) sInstance.mMediaRouteController = controller;
+        }
+    }
+
+    @Override
+    public void onPlaybackStateChanged(PlayerState oldState, PlayerState newState) {
+        onLockScreenPlaybackStateChanged(oldState, newState);
+    }
+
+    protected abstract void onLockScreenPlaybackStateChanged(PlayerState oldState,
+            PlayerState newState);
+
+    protected abstract boolean isPlaying();
+}