[PPAPI][MediaStream] Support configure for video input.

ppapi/shared_impl/media_stream_video_track_shared.cc

+// 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.
+
+#include "ppapi/shared_impl/media_stream_video_track_shared.h"
+
+#include "base/logging.h"
+
+namespace {
+
+const int32_t kMaxWidth = 4069;
+const int32_t kMaxHeight = 4069;
+
+}  // namespace
+
+namespace ppapi {
+
+// static
+bool MediaStreamVideoTrackShared::VerifyAttributes(
+    const Attributes& attributes) {
+  if (attributes.mask & Attributes::MASK_BUFFERS) {
+    if (attributes.buffers < 0)
+      return false;
+  } else if (attributes.buffers) {

[Ronghua Wu (Left Chromium), 2014/02/12 19:54:15]

can the value 0 means not set instead of using an additional mask?

[Peng, 2014/02/13 17:19:11]

My idea is:

If the mask is 1 and value is 0. it means to use the default value.
if the mask is 0, it means to use old value (set by previous Configure() call)
instead the default value.

WDYT?

+    return false;
+  }
+
+  if (attributes.mask & Attributes::MASK_FORMAT) {
+    if (attributes.format < PP_VIDEOFRAME_FORMAT_UNKNOWN ||
+        attributes.format > PP_VIDEOFRAME_FORMAT_LAST) {
+      return false;
+    }
+  } else if (attributes.format) {
+    return false;
+  }
+
+  if (attributes.mask & Attributes::MASK_WIDTH) {
+    if (attributes.width < 0 || attributes.width > kMaxWidth)
+      return false;
+    if (attributes.width & 0x3)
+      return false;
+  } else if (attributes.width) {
+    return false;
+  }
+
+  if (attributes.mask & Attributes::MASK_HEIGHT) {
+    if (attributes.height < 0 || attributes.height > kMaxHeight)
+      return false;
+    if (attributes.height & 0x3)
+      return false;
+  } else if (attributes.height) {
+    return false;
+  }
+
+  return true;
+}
+
+}  // namespace ppapi