DO NOT COMMIT - DialogSurface initial implementation.

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

+// 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.os.Handler;
+import android.os.HandlerThread;
+import android.os.IBinder;
+
+import org.chromium.base.ContextUtils;
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.annotations.JNINamespace;
+
+/**
+ * Singleton class to create and manage DialogSurfaceControllers.  Normally,
+ * you won't need to access this directly.  Instead, see the native wrappers
+ * in dialog_surface_manager.cc for usage.
+ *
+ * The wrappers do roughly the following on the gpu side:
+ *  - Create an IDialogSurfaceCallback.  For native, DialogSurfaceCallback hides
+ *    the threading issues and provides the java peer.
+ *  - Get an IDialogSurfaceManager from the browser via ChildProcessCallback .
+ *  - controller = IDialogSurfaceManager.createSurface(callback)
+ *    This calls into the browser, and returns an IDialogController IBinder.
+ *  - Wrap the controller in a DialogSurfaceControllerWrapper.  This provides
+ *    the JNI bindings for native.
+ *  - Expect callbacks on the callback to let you know when the underlying
+ *    android surface state changes.
+ *  - Use the surface.
+ *  - Call IDialogSurfaceController::release() to destroy the surface when done.
+ */
+@JNINamespace("media")
+public class DialogSurfaceManager extends IDialogSurfaceManager.Stub {
+    private static final String TAG = "cr_media";
+    private static DialogSurfaceManager sInstance;
+
+    private final Context mContext;
+
+    // We maintain a thread with a Looper for the DialogSurfaceControllers to use,
+    // since Dialog requires one.  We don't want this to be the native thread
+    // that's used to create them, because it probably also has a native message
+    // loop.  Including a looper on it is not a good idea.
+    private HandlerThread mThread;
+    private Handler mHandler;
+
+    // Number of SurfaceControllers that have been created but not released.
+    private int mNumSurfaces;
+
+    // Maximum number of concurrent surfaces we allow.
+    private static int sMaxSurfaces = 1;

[watk, 2016/06/10 21:46:38]

final

[liberato (no reviews please), 2016/06/10 22:50:05]

Done.

+
+    private DialogSurfaceManager() {
+        mContext = ContextUtils.getApplicationContext();
+        mNumSurfaces = 0;
+    }
+
+    public static IBinder instance() {
+        if (sInstance == null) sInstance = new DialogSurfaceManager();
+
+        return sInstance.asBinder();
+    }
+
+    @Override
+    @CalledByNative
+    public IDialogSurfaceController createSurface(
+            IDialogSurfaceCallback callback, int x, int y, int width, int height) {
+        // Limit the number of concurrent surfaces.
+        if (mNumSurfaces >= sMaxSurfaces) return null;
+
+        ensureThread();
+
+        mNumSurfaces++;
+        return new DialogSurfaceController(mContext, this, mHandler, callback, x, y, width, height);
+    }
+
+    /**
+     * Called by controllers when they no longer need the thread.
+     */
+    public void notifyReleased(DialogSurfaceController controller) {
+        if (mNumSurfaces > 0) mNumSurfaces--;
+
+        // We don't stop the looper thread here, else android can get mad when
+        // it tries to send a message from the dialog on this thread.
+        // DialogSurfaceController might have to notify us separately to tell us
+        // when it's done with the thread, if we don't want to wait until then
+        // to start creating a new SV.
+        // Instead, we just avoid shutting down the thread at all for now.
+        /*
+        if (mNumSurfaces == 0) {
+            mThread.quitSafely();
+            mThread = null;
+            mHandler = null;
+        }
+        */
+    }
+
+    /**
+     * Make sure that mThread and mHandler are ready for use.
+     */
+    private void ensureThread() {
+        // Called on main thread only.
+        if (mThread != null) return;
+
+        mThread = new HandlerThread("DialogSurfaceThread");
+        mThread.start();
+        mHandler = new Handler(mThread.getLooper());
+    }
+}