Revert 98168, it caused compile errors on mac:

chrome/common/safe_browsing/csd.proto

Index: chrome/common/safe_browsing/csd.proto
===================================================================
--- chrome/common/safe_browsing/csd.proto	(revision 98169)
+++ chrome/common/safe_browsing/csd.proto	(working copy)
@@ -17,14 +17,9 @@
 
 message ClientPhishingRequest {
   // URL that the client visited.  The CGI parameters are stripped by the
-  // client.  This field is ONLY set for UMA-enabled users.
-  optional string url = 1;
+  // client.
+  required string url = 1;
 
-  // A 5-byte SHA-256 hash prefix of the URL, in SafeBrowsing host sufffix/path
-  // prefix form with query parameters stripped (i.e. "www.example.com/1/2/").
-  // Unlike "url", this is sent for all users.
-  optional bytes suffix_prefix_hash = 10;
-
   // Score that was computed on the client.  Value is between 0.0 and 1.0.
   // The larger the value the more likely the url is phishing.
   required float client_score = 2;