Added new histogram for analyzing SDCH corruption detection cases.

net/base/sdch_manager.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Provides global database of differential decompression dictionaries for the
 // SDCH filter (processes sdch enconded content).
 
 // Exactly one instance of SdchManager is built, and all references are made
 // into that collection.
 //
@@ skipping 109 matching lines @@
     MULTIENCODING_FOR_NON_SDCH_REQUEST = 50,
     SDCH_CONTENT_ENCODE_FOR_NON_SDCH_REQUEST = 51,
 
     // Dictionary manager issues.
     DOMAIN_BLACKLIST_INCLUDES_TARGET = 61,
 
     // Problematic decode recovery methods.
     META_REFRESH_RECOVERY = 70,            // Dictionary not found.
     // defunct =  71, // Almost the same as META_REFRESH_UNSUPPORTED.
     // defunct = 72,  // Almost the same as CACHED_META_REFRESH_UNSUPPORTED.
-    // defunct = 73,  // PASSING_THROUGH_NON_SDCH plus DISCARD_TENTATIVE_SDCH.
+    // defunct = 73,  // PASSING_THROUGH_NON_SDCH plus
+                      // RESPONSE_TENTATIVE_SDCH in ../filter/sdch_filter.cc.
     META_REFRESH_UNSUPPORTED = 74,         // Unrecoverable error.
     CACHED_META_REFRESH_UNSUPPORTED = 75,  // As above, but pulled from cache.
     PASSING_THROUGH_NON_SDCH = 76,  // Tagged sdch but missing dictionary-hash.
     INCOMPLETE_SDCH_CONTENT = 77,   // Last window was not completely decoded.
     PASS_THROUGH_404_CODE = 78,     // URL not found message passing through.
 
     // This next report is very common, and not really an error scenario, but
     // it exercises the error recovery logic.
     PASS_THROUGH_OLD_CACHED = 79,   // Back button got pre-SDCH cached content.
 
     // Common decoded recovery methods.
     META_REFRESH_CACHED_RECOVERY = 80,  // Probably startup tab loading.
-    DISCARD_TENTATIVE_SDCH = 81,        // Server decided not to use sdch.
+    // defunct = 81, // Now tracked by ResponseCorruptionDetectionCause histo.
 
     // Non SDCH problems, only accounted for to make stat counting complete
     // (i.e., be able to be sure all dictionary advertisements are accounted
     // for).
 
     UNFLUSHED_CONTENT = 90,    // Possible error in filter chaining.
     // defunct = 91,           // MISSING_TIME_STATS (Should never happen.)
     CACHE_DECODED = 92,        // No timing stats recorded.
     // defunct = 93,           // OVER_10_MINUTES (No timing stats recorded.)
     UNINITIALIZED = 94,        // Filter never even got initialized.
@@ skipping 227 matching lines @@
   ExperimentSet allow_latency_experiment_;
 
   int fetches_count_for_testing_;
 
   DISALLOW_COPY_AND_ASSIGN(SdchManager);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_SDCH_MANAGER_H_