Remove use of void** from HttpResponseHeaders::EnumerateHeaderLines

chrome/browser/mod_pagespeed/mod_pagespeed_metrics.cc

Index: chrome/browser/mod_pagespeed/mod_pagespeed_metrics.cc
diff --git a/chrome/browser/mod_pagespeed/mod_pagespeed_metrics.cc b/chrome/browser/mod_pagespeed/mod_pagespeed_metrics.cc
index 6ef2d29b84e029cf44d86900f41e2868d6e100f4..f007a54b69f41e16a138bbf61d764e0799c9b847 100644
--- a/chrome/browser/mod_pagespeed/mod_pagespeed_metrics.cc
+++ b/chrome/browser/mod_pagespeed/mod_pagespeed_metrics.cc
@@ -86,10 +86,10 @@ void RecordMetrics(const content::ResourceType resource_type,
   if (!response_headers)
     return;
 
-  void* iter = nullptr;
+  size_t iter = 0;
   std::string name;
   std::string value;
-  while (response_headers->EnumerateHeaderLines(&iter, &name, &value)) {
+  while (response_headers->EnumerateHeaderLines(iter, &name, &value)) {
     if (name == kModPagespeedHeader) {
       // Bucket 1 counts occurrences of the X-Mod-Pagespeed header.
       UMA_HISTOGRAM_ENUMERATION(kPagespeedServerHistogram,