Reimplement devfs in dart. Implementation now writes to disk.

runtime/vm/service_isolate.cc

Index: runtime/vm/service_isolate.cc
diff --git a/runtime/vm/service_isolate.cc b/runtime/vm/service_isolate.cc
index c73c1769c52403a8631a0b871225179febbedfd8..e85a5c03de1d191e77df65061718d8a0c78a6ecb 100644
--- a/runtime/vm/service_isolate.cc
+++ b/runtime/vm/service_isolate.cc
@@ -7,7 +7,6 @@
 #include "vm/compiler.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
-#include "vm/dev_fs.h"
 #include "vm/isolate.h"
 #include "vm/lockers.h"
 #include "vm/message.h"
@@ -458,9 +457,6 @@ void ServiceIsolate::Run() {
   // Grab the isolate create callback here to avoid race conditions with tests
   // that change this after Dart_Initialize returns.
   create_callback_ = Isolate::CreateCallback();
-  if (FLAG_support_service) {
-    DevFS::Init();
-  }
   Dart::thread_pool()->Run(new RunServiceTask());
 }
 
@@ -509,9 +505,6 @@ void ServiceIsolate::Shutdown() {
     free(server_address_);
     server_address_ = NULL;
   }
-  if (FLAG_support_service) {
-    DevFS::Cleanup();
-  }
 }