Remove the task tracking stuff in the bindings.

mojo/public/cpp/environment/lib/logging_only_environment.cc

Index: mojo/public/cpp/environment/lib/logging_only_environment.cc
diff --git a/mojo/public/cpp/environment/lib/logging_only_environment.cc b/mojo/public/cpp/environment/lib/logging_only_environment.cc
index b6b97e61eb677065e71a3dff2a28b4cab89a65b2..22ea801546ac35b74459c45ba9456805c99ef2cc 100644
--- a/mojo/public/cpp/environment/lib/logging_only_environment.cc
+++ b/mojo/public/cpp/environment/lib/logging_only_environment.cc
@@ -15,8 +15,7 @@ namespace mojo {
 Environment::Environment() {}
 
 Environment::Environment(const MojoAsyncWaiter* default_async_waiter,
-                         const MojoLogger* default_logger,
-                         const TaskTracker* default_task_tracker) {}
+                         const MojoLogger* default_logger) {}
 
 Environment::~Environment() {}
 
@@ -31,11 +30,6 @@ const MojoLogger* Environment::GetDefaultLogger() {
 }
 
 // static
-const TaskTracker* Environment::GetDefaultTaskTracker() {
-  return nullptr;
-}
-
-// static
 void Environment::InstantiateDefaultRunLoop() {}
 
 // static