Reduce CPU usage when no isolates need to be profiled.

runtime/bin/utils.h

 // Copyright (c) 2012, 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.
 
 #ifndef BIN_UTILS_H_
 #define BIN_UTILS_H_
 
 #include <stdlib.h>
 #include <string.h>
 
@@ skipping 71 matching lines @@
   static void FreeUnicodeArgv(wchar_t** argv);
 };
 
 class TimerUtils {
  public:
   static int64_t GetCurrentTimeMicros();
   static int64_t GetCurrentTimeMilliseconds();
   static void Sleep(int64_t millis);
 };
 
+class ProfilerBlocker {

[Anders Johnsen, 2014/05/25 18:36:34]

Stuff like this usually go into dartutils.h.

[Cutch, 2014/05/26 06:59:35]

Done and renamed to ScopedBlockingCall

+ public:
+  ProfilerBlocker() {
+    Dart_BlockProfiler();
+  }
+
+  ~ProfilerBlocker() {
+    Dart_UnblockProfiler();
+  }
+};
+
 }  // namespace bin
 }  // namespace dart
 
 #endif  // BIN_UTILS_H_