Revised CL for customisable logging (replacing printfs).

runtime/bin/log.h

Index: runtime/bin/log.h
===================================================================
--- runtime/bin/log.h	(revision 0)
+++ runtime/bin/log.h	(revision 0)
@@ -0,0 +1,37 @@
+// 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_LOG_H_
+#define BIN_LOG_H_
+
+#include <stdarg.h>
+
+#include "platform/globals.h"
+
+class Log {
+ public:
+  // Print formatted output for debugging.
+  static void Print(const char* format, ...) PRINTF_ATTRIBUTE(1, 2) {
+    va_list args;
+    va_start(args, format);
+    VPrint(format, args);
+    va_end(args);
+  }
+
+  static void VPrint(const char* format, va_list args);
+
+  static void PrintErr(const char* format, ...) PRINTF_ATTRIBUTE(1, 2) {
+    va_list args;
+    va_start(args, format);
+    VPrintErr(format, args);
+    va_end(args);
+  }
+
+  static void VPrintErr(const char* format, va_list args);
+
+  DISALLOW_ALLOCATION();
+  DISALLOW_IMPLICIT_CONSTRUCTORS(Log);
+};
+
+#endif  // BIN_LOG_H_