Add UMA stats for predicted process counts with out-of-process iframes.

chrome/browser/memory_details.h

Index: chrome/browser/memory_details.h
diff --git a/chrome/browser/memory_details.h b/chrome/browser/memory_details.h
index 66094f2563a3f4a6384aa291f1d6d53dddd118fa..89692e206422cd187a8051798a1e9364dae23025 100644
--- a/chrome/browser/memory_details.h
+++ b/chrome/browser/memory_details.h
@@ -10,6 +10,7 @@
 #include "base/memory/ref_counted.h"
 #include "base/process_util.h"
 #include "base/strings/string16.h"
+#include "chrome/browser/site_details.h"
 #include "content/public/common/process_type.h"
 
 // We collect data about each browser process.  A browser may
@@ -76,6 +77,10 @@ struct ProcessData {
   string16 name;
   string16 process_name;
   ProcessMemoryInformationList processes;
+
+  // Track site data for predicting process counts with out-of-process iframes.
+  // See site_details.h.
+  BrowserContextSiteDataMap site_data;
 };
 
 #if defined(OS_MACOSX)