Histogram the scheme of an origin on the 1st navigation to it.

chrome/browser/profiles/off_the_record_profile_io_data.h

Index: chrome/browser/profiles/off_the_record_profile_io_data.h
diff --git a/chrome/browser/profiles/off_the_record_profile_io_data.h b/chrome/browser/profiles/off_the_record_profile_io_data.h
index 17cd658e779e3c12c12718e86fd5a5bcd3cd4e1b..7e3ff053b06307145b46a3b11bce8e161a928a52 100644
--- a/chrome/browser/profiles/off_the_record_profile_io_data.h
+++ b/chrome/browser/profiles/off_the_record_profile_io_data.h
@@ -5,6 +5,8 @@
 #ifndef CHROME_BROWSER_PROFILES_OFF_THE_RECORD_PROFILE_IO_DATA_H_
 #define CHROME_BROWSER_PROFILES_OFF_THE_RECORD_PROFILE_IO_DATA_H_
 
+#include <set>
+
 #include "base/callback.h"
 #include "base/containers/hash_tables.h"
 #include "base/files/file_path.h"
@@ -14,6 +16,7 @@
 #include "chrome/browser/custom_handlers/protocol_handler_registry.h"
 #include "chrome/browser/profiles/profile_io_data.h"
 #include "chrome/browser/profiles/storage_partition_descriptor.h"
+#include "url/origin.h"
 
 class ChromeURLRequestContextGetter;
 class Profile;
@@ -106,6 +109,8 @@ class OffTheRecordProfileIOData : public ProfileIOData {
     DISALLOW_COPY_AND_ASSIGN(Handle);
   };
 
+  bool HaveAlreadySeenOrigin(const url::Origin& origin) override;
+
  private:
   friend class base::RefCountedThreadSafe<OffTheRecordProfileIOData>;
 
@@ -159,6 +164,8 @@ class OffTheRecordProfileIOData : public ProfileIOData {
   mutable scoped_ptr<net::SdchManager> sdch_manager_;
   mutable scoped_ptr<net::SdchOwner> sdch_policy_;
 
+  std::set<url::Origin> origins_seen_;
+
   DISALLOW_COPY_AND_ASSIGN(OffTheRecordProfileIOData);
 };