Revert "Added isolate + thread high watermark tracking to Observatory"

runtime/vm/isolate.cc

Index: runtime/vm/isolate.cc
diff --git a/runtime/vm/isolate.cc b/runtime/vm/isolate.cc
index 32009f68698c8db654b4e525fe4cd1c16cfab078..622f9c117bced5e4be56cc91414330a55135cfc0 100644
--- a/runtime/vm/isolate.cc
+++ b/runtime/vm/isolate.cc
@@ -776,7 +776,6 @@ Isolate::Isolate(const Dart_IsolateFlags& api_flags)
       single_step_(false),
       thread_registry_(new ThreadRegistry()),
       safepoint_handler_(new SafepointHandler(this)),
-      memory_high_watermark_(0),
       message_notify_callback_(NULL),
       name_(NULL),
       debugger_name_(NULL),
@@ -2109,8 +2108,7 @@ void Isolate::PrintJSON(JSONStream* stream, bool ref) {
     }
   }
 
-  jsobj.AddPropertyF("_memoryHighWatermark", "%u", memory_high_watermark_);
-  jsobj.AddProperty("_threads", thread_registry_);
+  jsobj.AddProperty("threads", thread_registry_);
 }
 #endif
 
@@ -2660,8 +2658,6 @@ Thread* Isolate::ScheduleThread(bool is_mutator, bool bypass_safepoint) {
     thread = thread_registry()->GetFreeThreadLocked(this, is_mutator);
     ASSERT(thread != NULL);
 
-    thread->ResetHighWatermark();
-
     // Set up other values and set the TLS value.
     thread->isolate_ = this;
     ASSERT(heap() != NULL);
@@ -2708,7 +2704,6 @@ void Isolate::UnscheduleThread(Thread* thread,
     // Ensure that the thread reports itself as being at a safepoint.
     thread->EnterSafepoint();
   }
-  UpdateMemoryHighWatermark();
   OSThread* os_thread = thread->os_thread();
   ASSERT(os_thread != NULL);
   os_thread->DisableThreadInterrupts();
@@ -2729,15 +2724,6 @@ void Isolate::UnscheduleThread(Thread* thread,
 }
 
 
-void Isolate::UpdateMemoryHighWatermark() {
-  const intptr_t thread_watermarks_total =
-      thread_registry()->ThreadHighWatermarksTotalLocked();
-  if (thread_watermarks_total > memory_high_watermark_) {
-    memory_high_watermark_ = thread_watermarks_total;
-  }
-}
-
-
 static RawInstance* DeserializeObject(Thread* thread,
                                       uint8_t* obj_data,
                                       intptr_t obj_len) {