[cc] Pass on BeginFrameAcks from CompositorEBFS through RWHVAura, DFH.

cc/ipc/begin_frame_args_struct_traits.cc

Index: cc/ipc/begin_frame_args_struct_traits.cc
diff --git a/cc/ipc/begin_frame_args_struct_traits.cc b/cc/ipc/begin_frame_args_struct_traits.cc
new file mode 100644
index 0000000000000000000000000000000000000000..8ba827dbe1b4d6b4c0e719cd93c6346b13169fb8
--- /dev/null
+++ b/cc/ipc/begin_frame_args_struct_traits.cc
@@ -0,0 +1,39 @@
+// Copyright 2017 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 "cc/ipc/begin_frame_args_struct_traits.h"
+#include "ipc/ipc_message_utils.h"
+#include "mojo/common/common_custom_types_struct_traits.h"
+
+namespace mojo {
+
+// static
+bool StructTraits<cc::mojom::BeginFrameArgsDataView, cc::BeginFrameArgs>::Read(
+    cc::mojom::BeginFrameArgsDataView data,
+    cc::BeginFrameArgs* out) {
+  if (!data.ReadFrameTime(&out->frame_time) ||
+      !data.ReadDeadline(&out->deadline) ||
+      !data.ReadInterval(&out->interval)) {
+    return false;
+  }
+  out->source_id = data.source_id();
+  out->sequence_number = data.sequence_number();
+  // TODO(eseckler): Use EnumTraits for |type|.
+  out->type = static_cast<cc::BeginFrameArgs::BeginFrameArgsType>(data.type());
+  out->on_critical_path = data.on_critical_path();
+  return true;
+}
+
+// static
+bool StructTraits<cc::mojom::BeginFrameAckDataView, cc::BeginFrameAck>::Read(
+    cc::mojom::BeginFrameAckDataView data,
+    cc::BeginFrameAck* out) {
+  out->source_id = data.source_id();
+  out->sequence_number = data.sequence_number();
+  out->latest_confirmed_sequence_number =
+      data.latest_confirmed_sequence_number();
+  return true;
+}
+
+}  // namespace mojo