Add attributions so printf like functions can have their arguments checked.

runtime/platform/assert.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 PLATFORM_ASSERT_H_
 #define PLATFORM_ASSERT_H_
 
 // TODO(5411406): include sstream for now, once we have a Utils::toString()
 // implemented for all the primitive types we can replace the usage of
 // sstream by Utils::toString()
@@ skipping 15 matching lines @@
 class DynamicAssertionHelper {
  public:
   enum Kind {
     ASSERT,
     EXPECT
   };
 
   DynamicAssertionHelper(const char* file, int line, Kind kind)
       : file_(file), line_(line), kind_(kind) { }
 
-  void Fail(const char* format, ...);
+  void Fail(const char* format, ...) PRINTF_ATTRIBUTE(2, 3);
 
 #if defined(TESTING)
   template<typename E, typename A>
   void Equals(const E& expected, const A& actual);
 
   template<typename E, typename A>
   void NotEquals(const E& not_expected, const A& actual);
 
   template<typename E, typename A, typename T>
   void FloatEquals(const E& expected, const A& actual, const T& tol);
@@ skipping 295 matching lines @@
 #define WARN(error)                                                           \
   dart::Expect(__FILE__, __LINE__).Fail("%s", error)
 
 #define WARN1(format, p1)                                                     \
   dart::Expect(__FILE__, __LINE__).Fail(format, (p1))
 
 #define WARN2(format, p1, p2)                                                 \
   dart::Expect(__FILE__, __LINE__).Fail(format, (p1), (p2))
 
 #endif  // PLATFORM_ASSERT_H_