List sync points to wait on in AsyncFlush message

gpu/command_buffer/client/gles2_implementation.cc

Index: gpu/command_buffer/client/gles2_implementation.cc
diff --git a/gpu/command_buffer/client/gles2_implementation.cc b/gpu/command_buffer/client/gles2_implementation.cc
index 1916e7d2008d64b32dc71cc81d7211411e281237..50cd1e06562a60143f1f2897344f929c710724a9 100644
--- a/gpu/command_buffer/client/gles2_implementation.cc
+++ b/gpu/command_buffer/client/gles2_implementation.cc
@@ -3756,6 +3756,14 @@ void GLES2Implementation::RetireSyncPointCHROMIUM(GLuint sync_point) {
   gpu_control_->RetireSyncPoint(sync_point);
 }
 
+void GLES2Implementation::WaitSyncPointCHROMIUM(GLuint sync_point) {
+  GPU_CLIENT_SINGLE_THREAD_CHECK();
+  GPU_CLIENT_LOG("[" << GetLogPrefix() << "] glWaitSyncPointCHROMIUM("
+                     << sync_point << ")");
+  helper_->WillWaitOnSyncPoint(sync_point);
+  CheckGLError();
+}
+
 namespace {
 
 bool ValidImageFormat(GLenum internalformat) {