Http cache: Measure back navigations on the infinite cache simulation.

net/http/http_cache_transaction.cc

 // Copyright (c) 2012 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.
 
 #include "net/http/http_cache_transaction.h"
 
 #include "build/build_config.h"
 
 #if defined(OS_POSIX)
 #include <unistd.h>
@@ skipping 246 matching lines @@
     return ERR_UNEXPECTED;
 
   SetRequest(net_log, request);
   if (infinite_cache_transaction_.get()) {
     if ((effective_load_flags_ & LOAD_BYPASS_CACHE) ||
         (effective_load_flags_ & LOAD_ONLY_FROM_CACHE) ||
         (effective_load_flags_ & LOAD_DISABLE_CACHE) ||
         (effective_load_flags_ & LOAD_VALIDATE_CACHE) ||
         (effective_load_flags_ & LOAD_PREFERRING_CACHE) ||
         partial_.get()) {
+      if (effective_load_flags_ & LOAD_PREFERRING_CACHE)
+        infinite_cache_transaction_->OnBackNavigation();
       infinite_cache_transaction_.reset();
     } else {
       infinite_cache_transaction_->OnRequestStart(request);
     }
   }
 
   // We have to wait until the backend is initialized so we start the SM.
   next_state_ = STATE_GET_BACKEND;
   int rv = DoLoop(OK);
 
@@ skipping 2207 matching lines @@
 }
 
 int HttpCache::Transaction::ResetCacheIOStart(int return_value) {
   DCHECK(cache_io_start_.is_null());
   if (return_value == ERR_IO_PENDING)
     cache_io_start_ = base::TimeTicks::Now();
   return return_value;
 }
 
 }  // namespace net