Adds UMA histogram metrics for SafeBrowsing PVer4 methods.

chrome/browser/safe_browsing/protocol_manager.h

Index: chrome/browser/safe_browsing/protocol_manager.h
diff --git a/chrome/browser/safe_browsing/protocol_manager.h b/chrome/browser/safe_browsing/protocol_manager.h
index 4e6c6771ef8337da92e823b34d718f2be4bba5a9..1efbc0f0e77c7dd1ed7dec12919efe24c46d3eb2 100644
--- a/chrome/browser/safe_browsing/protocol_manager.h
+++ b/chrome/browser/safe_browsing/protocol_manager.h
@@ -163,6 +163,9 @@ class SafeBrowsingProtocolManager : public net::URLFetcherDelegate,
     // Gethash attempted during error backoff, no request sent.
     GET_HASH_BACKOFF_ERROR,
 
+    // Gethash attempted before min wait duration elapsed, no request sent.
+    GET_HASH_MIN_WAIT_DURATION_ERROR,
+
     // Memory space for histograms is determined by the max.  ALWAYS
     // ADD NEW VALUES BEFORE THIS ONE.
     GET_HASH_RESULT_MAX
@@ -173,6 +176,9 @@ class SafeBrowsingProtocolManager : public net::URLFetcherDelegate,
   static void RecordGetHashResult(bool is_download,
                                   ResultType result_type);
 
+  // Record a V4 GetHash result.
+  static void RecordGetV4HashResult(ResultType result_type);
+
   // Record HTTP response code when there's no error in fetching an HTTP
   // request, and the error code, when there is.
   // |metric_name| is the name of the UMA metric to record the response code or