Avoid wrong memory access due to double substitution and %%

tests/skia_test.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "CrashHandler.h"
 #include "OverwriteLine.h"
 #include "Resources.h"
@@ skipping 146 matching lines @@
         }
 #ifdef SK_DEBUG
         header.append(" SK_DEBUG");
 #else
         header.append(" SK_RELEASE");
 #endif
         header.appendf(" skia_arch_width=%d", (int)sizeof(void*) * 8);
         if (FLAGS_veryVerbose) {
             header.appendf("\n");
         }
-        SkDebugf(header.c_str());
+        SkDebugf("%s", header.c_str());
     }
 
 
     // Count tests first.
     int total = 0;
     int toRun = 0;
 
     for (const TestRegistry* iter = TestRegistry::Head(); iter;
          iter = iter->next()) {
         const Test& test = iter->factory();
@@ skipping 50 matching lines @@
     SkDebugf("\n");
     return (status.failCount() == 0) ? 0 : 1;
 }
 
 #if !defined(SK_BUILD_FOR_IOS) && !defined(SK_BUILD_FOR_NACL)
 int main(int argc, char** argv) {
     SkCommandLineFlags::Parse(argc, argv);
     return test_main();
 }
 #endif