Make async waiter explicit MojoGLES2CreateContext param

mojo/cc/context_provider_mojo.cc

Index: mojo/cc/context_provider_mojo.cc
diff --git a/mojo/cc/context_provider_mojo.cc b/mojo/cc/context_provider_mojo.cc
index 1dd62d8a08bd8c3fda2a9e838ba8afeee7d04b69..358f8f11fecdcaf4595ec3b07411911eabea0ea5 100644
--- a/mojo/cc/context_provider_mojo.cc
+++ b/mojo/cc/context_provider_mojo.cc
@@ -5,6 +5,7 @@
 #include "mojo/cc/context_provider_mojo.h"
 
 #include "base/logging.h"
+#include "mojo/public/cpp/environment/environment.h"
 
 namespace mojo {
 
@@ -19,7 +20,8 @@ bool ContextProviderMojo::BindToCurrentThread() {
   context_ = MojoGLES2CreateContext(
       command_buffer_handle_.release().value(),
       &ContextLostThunk,
-      this);
+      this,
+      Environment::GetDefaultAsyncWaiter());
   return !!context_;
 }