Add support for dumping code in jitdump file format

runtime/vm/code_observers.cc

Index: runtime/vm/code_observers.cc
diff --git a/runtime/vm/code_observers.cc b/runtime/vm/code_observers.cc
index 487337136c137545f93433cfa35be01ff064b5bb..7c0a1ff6ba3a7a29fd57fb5c7f8f70bfc0813ee0 100644
--- a/runtime/vm/code_observers.cc
+++ b/runtime/vm/code_observers.cc
@@ -2,12 +2,14 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-#include "vm/code_observers.h"
+#include "platform/thread.h"

[Ivan Posva, 2014/02/25 08:09:04]

The directly associated header is always included first. Please move this below
"vm/code_observers.h"

[Cutch, 2014/02/26 22:28:28]

Done.

 
+#include "vm/code_observers.h"
 #include "vm/os.h"
 
 namespace dart {
 
+Mutex* CodeObservers::mutex_ = NULL;
 intptr_t CodeObservers::observers_length_ = 0;
 CodeObserver** CodeObservers::observers_ = NULL;
 
@@ -56,6 +58,9 @@ void CodeObservers::DeleteAll() {
 
 
 void CodeObservers::InitOnce() {
+  ASSERT(mutex_ == NULL);
+  mutex_ = new Mutex();
+  ASSERT(mutex_ != NULL);
   OS::RegisterCodeObservers();
 }