Added isolate + thread high watermark tracking to Observatory

runtime/vm/thread_registry.cc

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // 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/thread_registry.h"
 
 #include "vm/isolate.h"
 #include "vm/json_stream.h"
 #include "vm/lockers.h"
 
@@ skipping 128 matching lines @@
   // Get thread structure from free list or create a new one.
   if (free_list_ == NULL) {
     thread = new Thread(isolate);
   } else {
     thread = free_list_;
     free_list_ = thread->next_;
   }
   return thread;
 }
 
+
 void ThreadRegistry::ReturnToFreelistLocked(Thread* thread) {
   ASSERT(thread != NULL);
   ASSERT(thread->os_thread_ == NULL);
   ASSERT(thread->isolate_ == NULL);
   ASSERT(thread->heap_ == NULL);
   ASSERT(threads_lock()->IsOwnedByCurrentThread());
   // Add thread to the free list.
   thread->next_ = free_list_;
   free_list_ = thread;
 }
 
+
+intptr_t ThreadRegistry::ThreadHighWatermarksTotalLocked() const {
+  ASSERT(threads_lock()->IsOwnedByCurrentThread());
+  intptr_t max_memory_usage_total = 0;
+  Thread* current = active_list_;
+  while (current != NULL) {
+    max_memory_usage_total += current->GetThreadHighWatermark();
+    current = current->next_;
+  }
+  return max_memory_usage_total;
+}
+
 }  // namespace dart