DialogSurfaceManager implementation.

media/base/android/dialog_surface.h

+// 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.
+
+#ifndef MEDIA_BASE_ANDROID_DIALOG_SURFACE_H_
+#define MEDIA_BASE_ANDROID_DIALOG_SURFACE_H_
+
+#include <jni.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include <set>
+#include <string>
+
+#include "base/android/scoped_java_ref.h"
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/task_runner.h"
+#include "base/threading/thread_checker.h"
+#include "base/time/time.h"
+#include "media/base/media_export.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/gl/android/scoped_java_surface.h"
+
+namespace media {
+
+class DialogSurfaceCallback;
+class DialogSurfaceManager;
+
+// This class implements the C++ wrapper around a java DialogSurface.
+// All callbacks happen on the thread that it's constructed on.
+// Once the object is destroyed on that same thread, no further callbacks will
+// arrive.  In particular, it's safe to delete a DialogSurface during a
+// callback, and expect that no further callbacks will happen.
+// When a DialogSurface is deleted, the associated Android surface, if any, will
+// be destroyed.  This will be asynchronous.
+class MEDIA_EXPORT DialogSurface {
+ public:
+  // These must match DialogSurface.java

[boliu, 2017/01/04 01:48:44]

fwiw there is an automated way to generate enums that match in java and native,
eg net_errors_java. Though might be a bit overkill here..

[liberato (no reviews please), 2017/01/11 22:17:56]

Acknowledged.

+  //
+  // SURFACE_CREATED will be sent at most once an android surface is available
+  // via GetAndroidSurface.  Prior to SURFACE_CREATED, layout requests will be
+  // ignored, and GetAndroidSurface will return an empty surface.
+  //
+  // SURFACE_DESTROYED will be sent to indicate that the DialogSurface instance
+  // is no longer needd.  The application must quit using the Android Surface
+  // before this callback returns.  It is okay for SURFACE_DESTROYED to arrive
+  // without a pending SURFACE_CREATED, to indicate that no surface will arrive.
+  // In either case, the application must create a new DialogSurface instance
+  // if it wants another surface.
+  enum CallbackOp { SURFACE_CREATED = 0, SURFACE_DESTROYED = 1 };
+
+  // Callback type for finding out about the status of the surface.  While we
+  // don't use this directly, it lets us keep DialogSurfaceCallback as an
+  // implementation detail.
+  using Callback = base::Callback<void(CallbackOp)>;
+
+  // Configuration for the surface.
+  struct Config {
+    gfx::Rect rect;
+    // This may also include pixel format, is_secure, etc.
+  };
+
+  // |unwrapped_surface| is the IDialogSurface java instance, which
+  // we will take ownership of.  |callback| is the wrapped callback that it will
+  // use to communicate with us (DialogSurfaceCallback).
+  // Note: one generally doesn't want to call this directly.  Use
+  // DialogSurfaceManager instead.
+  DialogSurface(const base::android::JavaRef<jobject>& unwrapped_surface,
+                std::unique_ptr<DialogSurfaceCallback> callback);
+  ~DialogSurface();
+
+  // Schedule a relayout and/or reposition of the surface.  Calls before a
+  // SURFACE_CREATED callback, or after SURFACE_DESTROYED, are ignored.
+  void ScheduleLayout(const Config& config);
+
+  // Note that java does not have a reference to this object -- it knows only
+  // about the callback.  This is helpful, since we don't need to synchronize
+  // our destruction with anything going on in java.  DialogSurfaceCallback
+  // handles synchronization of itself.
+
+  // Return the Androird surface, or null.  This will return null until the
+  // callback is called with SURFACE_CREATED.  You may take ownership of this
+  // surface, or not.
+  gl::ScopedJavaSurface& GetAndroidSurface();
+
+ protected:
+  bool CalledOnValidThread() const;
+
+  // Set the java surface from the callback.
+  void OnAndroidSurface(const base::android::JavaRef<jobject>& jsurface);
+
+ private:
+  // Java DialogSurfaceWrapper instance.
+  base::android::ScopedJavaGlobalRef<jobject> j_wrapped_surface_;
+
+  // Callback that's associated with this surface.  We maintain ownership of it
+  // so that the native object stays around while we do.  Future callbacks will
+  // be cancelled by DialogSurfaceCallback once the object is deleted.
+  std::unique_ptr<DialogSurfaceCallback> wrapped_callback_;
+
+  gl::ScopedJavaSurface android_surface_;
+
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(DialogSurface);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_ANDROID_DIALOG_SURFACE_H_