[HttpCache] LOAD_ONLY_FROM_CACHE should not imply LOAD_PREFERRING_CACHE

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"  // For OS_POSIX
 
 #if defined(OS_POSIX)
 #include <unistd.h>
@@ skipping 1966 matching lines @@
   return true;
 }
 
 int HttpCache::Transaction::BeginCacheRead() {
   // We don't support any combination of LOAD_ONLY_FROM_CACHE and byte ranges.
   if (response_.headers->response_code() == 206 || partial_) {
     NOTREACHED();
     return ERR_CACHE_MISS;
   }
 
-  if (request_->method == "HEAD")
-    FixHeadersForHead();
-
   // We don't have the whole resource.
   if (truncated_)
     return ERR_CACHE_MISS;
 
+  // Verify that the response is still valid unless LOAD_SKIP_CACHE_VALIDATION
+  // is set.
+  if (!(effective_load_flags_ & LOAD_SKIP_CACHE_VALIDATION) &&
+      RequiresValidation() != VALIDATION_NONE)

[gavinp, 2016/10/07 16:45:09]

Nit: Doesn't this need a { per our style guide?

[jkarlin, 2016/10/13 15:33:58]

Done.

+    return ERR_CACHE_MISS;
+
+  if (request_->method == "HEAD")
+    FixHeadersForHead();
+
   if (entry_->disk_entry->GetDataSize(kMetadataIndex))
     next_state_ = STATE_CACHE_READ_METADATA;
 
   return OK;
 }
 
 int HttpCache::Transaction::BeginCacheValidation() {
   DCHECK_EQ(mode_, READ_WRITE);
 
   ValidationType required_validation = RequiresValidation();
@@ skipping 193 matching lines @@
   //  - watch out for cached responses that depend on authentication
 
   if (response_.vary_data.is_valid() &&
       !response_.vary_data.MatchesRequest(*request_,
                                           *response_.headers.get())) {
     vary_mismatch_ = true;
     validation_cause_ = VALIDATION_CAUSE_VARY_MISMATCH;
     return VALIDATION_SYNCHRONOUS;
   }
 
-  if (effective_load_flags_ & LOAD_PREFERRING_CACHE)
+  if (effective_load_flags_ & LOAD_SKIP_CACHE_VALIDATION)
     return VALIDATION_NONE;
 
   if (response_.unused_since_prefetch &&
       !(effective_load_flags_ & LOAD_PREFETCH) &&
       response_.headers->GetCurrentAge(
           response_.request_time, response_.response_time,
           cache_->clock_->Now()) < TimeDelta::FromMinutes(kPrefetchReuseMins)) {
     // The first use of a resource after prefetch within a short window skips
     // validation.
     return VALIDATION_NONE;
@@ skipping 721 matching lines @@
     default:
       NOTREACHED();
   }
 }
 
 void HttpCache::Transaction::OnIOComplete(int result) {
   DoLoop(result);
 }
 
 }  // namespace net