Implement MusGpuMemoryBufferManager

components/mus/common/gpu_service.cc

Index: components/mus/common/gpu_service.cc
diff --git a/components/mus/common/gpu_service.cc b/components/mus/common/gpu_service.cc
index 37c0635078b4a1920dddd9241ac26f1b235f6f59..73049e520580245420c5139a0ce9b3e9a5e6b61b 100644
--- a/components/mus/common/gpu_service.cc
+++ b/components/mus/common/gpu_service.cc
@@ -6,6 +6,7 @@
 
 #include "base/command_line.h"
 #include "base/memory/singleton.h"
+#include "base/threading/thread_restrictions.h"
 #include "components/mus/common/gpu_type_converters.h"
 #include "components/mus/common/mojo_gpu_memory_buffer_manager.h"
 #include "components/mus/common/switches.h"
@@ -72,10 +73,14 @@ scoped_refptr<gpu::GpuChannelHost> GpuService::EstablishGpuChannel(
   gpu::GPUInfo gpu_info;
   gpu_service->EstablishGpuChannel(base::Bind(
       &GpuChannelEstablishCallback, &client_id, &channel_handle, &gpu_info));
-  if (!gpu_service.WaitForIncomingResponse()) {
-    DLOG(WARNING)
-        << "Channel encountered error while establishing gpu channel.";
-    return nullptr;
+
+  {
+    base::ThreadRestrictions::ScopedAllowWait allow_wait;
+    if (!gpu_service.WaitForIncomingResponse()) {
+      DLOG(WARNING)
+          << "Channel encountered error while establishing gpu channel.";
+      return nullptr;
+    }
   }
   gpu_channel_ = gpu::GpuChannelHost::Create(this, client_id, gpu_info,
                                              channel_handle, &shutdown_event_,