Only send the FrameSinkId to client when it is necessary

services/ui/public/cpp/client_compositor_frame_sink.cc

Index: services/ui/public/cpp/client_compositor_frame_sink.cc
diff --git a/services/ui/public/cpp/client_compositor_frame_sink.cc b/services/ui/public/cpp/client_compositor_frame_sink.cc
index ef014e05ae77d58a8dbc11cf528072e859106aa0..487ef4dba3bf40963b51e683c91dfb7deaa23bae 100644
--- a/services/ui/public/cpp/client_compositor_frame_sink.cc
+++ b/services/ui/public/cpp/client_compositor_frame_sink.cc
@@ -5,9 +5,7 @@
 #include "services/ui/public/cpp/client_compositor_frame_sink.h"
 
 #include "base/bind.h"
-#include "base/command_line.h"
 #include "base/memory/ptr_util.h"
-#include "cc/base/switches.h"
 #include "cc/output/begin_frame_args.h"
 #include "cc/output/compositor_frame.h"
 #include "cc/output/compositor_frame_sink_client.h"
@@ -16,11 +14,11 @@ namespace ui {
 
 // static
 std::unique_ptr<ClientCompositorFrameSink> ClientCompositorFrameSink::Create(
-    const cc::FrameSinkId& frame_sink_id,
     scoped_refptr<cc::ContextProvider> context_provider,
     gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager,
     std::unique_ptr<ClientCompositorFrameSinkBinding>*
-        compositor_frame_sink_binding) {
+        compositor_frame_sink_binding,
+    bool enable_surface_synchronization) {
   cc::mojom::MojoCompositorFrameSinkPtr compositor_frame_sink;
   cc::mojom::MojoCompositorFrameSinkClientPtr compositor_frame_sink_client;
   cc::mojom::MojoCompositorFrameSinkClientRequest
@@ -31,9 +29,10 @@ std::unique_ptr<ClientCompositorFrameSink> ClientCompositorFrameSink::Create(
       MakeRequest(&compositor_frame_sink),
       compositor_frame_sink_client.PassInterface()));
   return base::WrapUnique(new ClientCompositorFrameSink(
-      frame_sink_id, std::move(context_provider), gpu_memory_buffer_manager,
+      std::move(context_provider), gpu_memory_buffer_manager,
       compositor_frame_sink.PassInterface(),
-      std::move(compositor_frame_sink_client_request)));
+      std::move(compositor_frame_sink_client_request),
+      enable_surface_synchronization));
 }
 
 ClientCompositorFrameSink::~ClientCompositorFrameSink() {}
@@ -82,33 +81,29 @@ void ClientCompositorFrameSink::SubmitCompositorFrame(
             frame.metadata.begin_frame_ack.sequence_number);
 
   gfx::Size frame_size = frame.render_pass_list.back()->output_rect.size();
-  if (!enable_surface_synchronization_ &&
-      (!local_surface_id_.is_valid() ||
-       frame_size != last_submitted_frame_size_)) {
-    local_surface_id_ = id_allocator_.GenerateId();
+  if (!local_surface_id_.is_valid() ||
+      frame_size != last_submitted_frame_size_) {
+    last_submitted_frame_size_ = frame_size;
+    if (!enable_surface_synchronization_)
+      local_surface_id_ = id_allocator_.GenerateId();
   }
   compositor_frame_sink_->SubmitCompositorFrame(local_surface_id_,
                                                 std::move(frame));
-  last_submitted_frame_size_ = frame_size;
 }
 
 ClientCompositorFrameSink::ClientCompositorFrameSink(
-    const cc::FrameSinkId& frame_sink_id,
     scoped_refptr<cc::ContextProvider> context_provider,
     gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager,
     cc::mojom::MojoCompositorFrameSinkPtrInfo compositor_frame_sink_info,
-    cc::mojom::MojoCompositorFrameSinkClientRequest client_request)
+    cc::mojom::MojoCompositorFrameSinkClientRequest client_request,
+    bool enable_surface_synchronization)
     : cc::CompositorFrameSink(std::move(context_provider),
                               nullptr,
                               gpu_memory_buffer_manager,
                               nullptr),
       compositor_frame_sink_info_(std::move(compositor_frame_sink_info)),
       client_request_(std::move(client_request)),
-      frame_sink_id_(frame_sink_id) {
-  enable_surface_synchronization_ =
-      base::CommandLine::ForCurrentProcess()->HasSwitch(
-          cc::switches::kEnableSurfaceSynchronization);
-}
+      enable_surface_synchronization_(enable_surface_synchronization) {}
 
 void ClientCompositorFrameSink::DidReceiveCompositorFrameAck(
     const cc::ReturnedResourceArray& resources) {