ppapi_proxy: Make DebugPrintf more usable....

src/shared/ppapi_proxy/utility.cc

 /*
  * Copyright 2010 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can
  * be found in the LICENSE file.
  */
 
 #include "native_client/src/shared/ppapi_proxy/utility.h"
 #include <stdarg.h>
 #include <stdlib.h>
 #include "native_client/src/shared/platform/nacl_check.h"
 #include "native_client/src/include/nacl_assert.h"
 
 namespace ppapi_proxy {
 
 const int foo = 5;
 
 void DebugPrintf(const char* format, ...) {
   static int printf_enabled = -1;
   if (printf_enabled == -1) {
     printf_enabled = (getenv("PPAPI_BROWSER_DEBUG") != NULL);
   }
   if (printf_enabled == 1) {
     va_list argptr;
     va_start(argptr, format);
-    vfprintf(stderr, format, argptr);
+    fprintf(stdout, "ppapi_proxy: ");
+    vfprintf(stdout, format, argptr);
     va_end(argptr);
-    fflush(stderr);
+    fflush(stdout);
   }
 }
 
 }  // namespace ppapi_proxy