Http cache: Allow caching of byte ranges without strong validators.

net/http/http_cache_transaction.cc

Index: net/http/http_cache_transaction.cc
diff --git a/net/http/http_cache_transaction.cc b/net/http/http_cache_transaction.cc
index f11d695579aea88b7090f45d65a7483b2c23b1be..c49f73d33b6390967a3fc29ee8348e014eae6de7 100644
--- a/net/http/http_cache_transaction.cc
+++ b/net/http/http_cache_transaction.cc
@@ -1559,15 +1559,6 @@ int HttpCache::Transaction::DoOverwriteCachedResponse() {
     return OK;
   }
 
-  if (handling_206_ && !CanResume(false)) {

[davidben, 2014/08/29 18:03:23]

CanResume checks for a few things other than HasStrongValidators, like a missing
Content-Length. Should that still skip writing to the cache or will the rest of
the logic handle it?

[rvargas (doing something else), 2014/08/29 19:34:27]

The rest of the logic will handle that. CanResume checks all conditions needed
to issue a conditional byte-range request, which we now don't consider to save a
response. If matching the stored data with a requested range fails, we bail out
before getting to the revalidation logic (PartialData::UpdateFromStoredHeaders)

-    // There is no point in storing this resource because it will never be used.
-    DoneWritingToEntry(false);
-    if (partial_.get())
-      partial_->FixResponseHeaders(response_.headers.get(), true);
-    next_state_ = STATE_PARTIAL_HEADERS_RECEIVED;
-    return OK;
-  }
-
   target_state_ = STATE_TRUNCATE_CACHED_DATA;
   next_state_ = truncated_ ? STATE_CACHE_WRITE_TRUNCATED_RESPONSE :
                              STATE_CACHE_WRITE_RESPONSE;
@@ -2307,9 +2298,10 @@ bool HttpCache::Transaction::ConditionalizeRequest() {
     return false;
   }
 
-  // We should have handled this case before.
-  DCHECK(response_.headers->response_code() != 206 ||
-         response_.headers->HasStrongValidators());
+  if (response_.headers->response_code() == 206 &&
+      !response_.headers->HasStrongValidators()) {
+    return false;
+  }
 
   // Just use the first available ETag and/or Last-Modified header value.
   // TODO(darin): Or should we use the last?