Update from https://crrev.com/312600

gpu/command_buffer/common/gles2_cmd_format.h

Index: gpu/command_buffer/common/gles2_cmd_format.h
diff --git a/gpu/command_buffer/common/gles2_cmd_format.h b/gpu/command_buffer/common/gles2_cmd_format.h
index b23cae3ac7e176d04f7cb6b4cce1fb4b76d5b9af..55fa4a1552658b74dba9e787ad5e0c1a3af787d1 100644
--- a/gpu/command_buffer/common/gles2_cmd_format.h
+++ b/gpu/command_buffer/common/gles2_cmd_format.h
@@ -42,6 +42,7 @@ typedef double GLclampd;
 typedef void GLvoid;
 typedef khronos_intptr_t GLintptr;
 typedef khronos_ssize_t  GLsizeiptr;
+typedef struct __GLsync *GLsync;
 
 namespace gpu {
 namespace gles2 {
@@ -63,6 +64,7 @@ enum IdNamespaces {
   kValuebuffers,
   kSamplers,
   kTransformFeedbacks,
+  kSyncs,
   kNumIdNamespaces
 };