Add IPC messages to transfer compositor protos

content/renderer/gpu/render_widget_compositor.cc

Index: content/renderer/gpu/render_widget_compositor.cc
diff --git a/content/renderer/gpu/render_widget_compositor.cc b/content/renderer/gpu/render_widget_compositor.cc
index 641946864ca300aa16117880873e619d7d43443a..98e11b17a67f2225de212a0cca2697f0b00ba283 100644
--- a/content/renderer/gpu/render_widget_compositor.cc
+++ b/content/renderer/gpu/render_widget_compositor.cc
@@ -10,6 +10,7 @@
 #include "base/command_line.h"
 #include "base/location.h"
 #include "base/logging.h"
+#include "base/numerics/safe_conversions.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/synchronization/lock.h"
@@ -31,10 +32,12 @@
 #include "cc/output/copy_output_result.h"
 #include "cc/output/latency_info_swap_promise.h"
 #include "cc/output/swap_promise.h"
+#include "cc/proto/compositor_message.pb.h"
 #include "cc/resources/single_release_callback.h"
 #include "cc/scheduler/begin_frame_source.h"
 #include "cc/trees/latency_info_swap_promise_monitor.h"
 #include "cc/trees/layer_tree_host.h"
+#include "cc/trees/remote_proto_channel.h"
 #include "components/scheduler/renderer/renderer_scheduler.h"
 #include "content/common/content_switches_internal.h"
 #include "content/common/gpu/client/context_provider_command_buffer.h"
@@ -215,6 +218,7 @@ RenderWidgetCompositor::RenderWidgetCompositor(
       compositor_deps_(compositor_deps),
       never_visible_(false),
       layout_and_paint_async_callback_(nullptr),
+      remote_proto_channel_receiver_(nullptr),
       weak_factory_(this) {
 }
 
@@ -968,6 +972,18 @@ void RenderWidgetCompositor::DidAbortSwapBuffers() {
   widget_->OnSwapBuffersAborted();
 }
 
+void RenderWidgetCompositor::SetProtoReceiver(ProtoReceiver* receiver) {
+  remote_proto_channel_receiver_ = receiver;
+}
+
+void RenderWidgetCompositor::SendCompositorProto(
+    const cc::proto::CompositorMessage& proto) {
+  size_t size = base::checked_cast<size_t>(proto.ByteSize());
+  std::vector<uint8_t> serialized(size);
+  proto.SerializeToArray(serialized.data(), serialized.size());

[David Trainor- moved to gerrit, 2015/11/17 00:58:34]

Hmm I should probably make this use proto.ByteSize() as the size of the array. 
I'm assuming the checked_cast will kill this if anything bad could happen
though?

[palmer, 2015/11/17 01:25:32]

Yep, checked_cast will CHECK if there is a problem. The way you have written it
here works just fine. If you wanted you could fold line 981 into line 982, but
it doesn't matter.

[David Trainor- moved to gerrit, 2015/11/17 04:52:26]

Ah okay thanks!  I tweaked this a bit to just make sure I'm passing the right
thing to the right method, but I guess I didn't have to.

+  widget_->ForwardCompositorProto(serialized);
+}
+
 void RenderWidgetCompositor::RecordFrameTimingEvents(
     scoped_ptr<cc::FrameTimingTracker::CompositeTimingSet> composite_events,
     scoped_ptr<cc::FrameTimingTracker::MainFrameTimingSet> main_frame_events) {
@@ -1005,6 +1021,21 @@ void RenderWidgetCompositor::SetSurfaceIdNamespace(
   layer_tree_host_->set_surface_id_namespace(surface_id_namespace);
 }
 
+void RenderWidgetCompositor::OnHandleCompositorProto(
+    const std::vector<uint8_t>& proto) {
+  DCHECK(remote_proto_channel_receiver_);
+
+  scoped_ptr<cc::proto::CompositorMessage> deserialized(
+      new cc::proto::CompositorMessage);
+  int size = base::checked_cast<int>(proto.size());
+  if (!deserialized->ParseFromArray(proto.data(), size)) {
+    LOG(ERROR) << "Unable to parse compositor proto.";
+    return;
+  }
+
+  remote_proto_channel_receiver_->OnProtoReceived(deserialized.Pass());
+}
+
 cc::ManagedMemoryPolicy RenderWidgetCompositor::GetGpuMemoryPolicy(
     const cc::ManagedMemoryPolicy& policy) {
   cc::ManagedMemoryPolicy actual = policy;