Mojom updates for Motown.

mojo/services/media/common/interfaces/media_state.mojom

Index: mojo/services/media/common/interfaces/media_state.mojom
diff --git a/mojo/services/media/common/interfaces/media_state.mojom b/mojo/services/media/common/interfaces/media_state.mojom
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+// 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.
+
+[DartPackage="mojo_services"]
+module mojo.media;
+
+// Expresses the overall state of a media component.
+enum MediaState {
+  // Unable to function due to error. Fault details are provided elsewhere.
+  FAULT,
+
+  // Intentionally disabled.
+  DISABLED,
+
+  // Requires preparation in order to function.
+  UNPREPARED,
+
+  // Preparation underway.
+  PREPARING,
+
+  // Fully prepared, rate zero (paused).
+  PREPARED,
+
+  // Fully prepared, rate non-zero.
+  PLAYING,

[johngro, 2015/12/10 21:46:02]

design question; we can defer action on this until later.

Should we be exposing clock concepts here?  What state do we go to if we were
playing and we pause, is that back to prepared?  How about a live stream?  Once
it is buffered, do we stay in prepared but discard stale data until we start to
play?

Perhaps PREPARED and PLAYING can be merged into just READY.  We could introduce
a separate BUFFERING state which we could transition to in an
underflow/re-buffer scenario, but we could also just bounce back and forth
between READY and PREPARING if we didn't want a separate state.

[dalesat, 2015/12/10 22:33:38]

Many good questions. I've renamed PREPARED -> PAUSED. There are many ways to go
with respect to factoring state. For now, I wanted something simple that would
drive UI in a straightforward manner.

+
+  // Stopped playing because end-of-stream was encountered.
+  ENDED
+};