Remove the task tracking stuff in the bindings.

mojo/environment/environment.cc

Index: mojo/environment/environment.cc
diff --git a/mojo/environment/environment.cc b/mojo/environment/environment.cc
index a5a424cb45ef08867872e4cf84206ecb66e42d0e..562bfe425c8ca90f24ed7078fcdbc3d418dd6b99 100644
--- a/mojo/environment/environment.cc
+++ b/mojo/environment/environment.cc
@@ -7,7 +7,6 @@
 #include "base/message_loop/message_loop.h"
 #include "mojo/environment/default_async_waiter.h"
 #include "mojo/environment/default_logger.h"
-#include "mojo/environment/default_task_tracker.h"
 
 namespace mojo {
 
@@ -36,11 +35,6 @@ const MojoLogger* Environment::GetDefaultLogger() {
 }
 
 // static
-const TaskTracker* Environment::GetDefaultTaskTracker() {
-  return &internal::kDefaultTaskTracker;
-}
-
-// static
 void Environment::InstantiateDefaultRunLoop() {
   CHECK(!base::MessageLoop::current());
   // Not leaked: accessible from |base::MessageLoop::current()|.