Cache failover to LOAD_PREFERRING_CACHE if network response suggests offline.

net/http/http_response_info.cc

Index: net/http/http_response_info.cc
diff --git a/net/http/http_response_info.cc b/net/http/http_response_info.cc
index 9c33ab4f53e8b0bef1ef03cb6c82cf16f7b6152a..a904b01ddc7bd691729288268b7b234364f6036f 100644
--- a/net/http/http_response_info.cc
+++ b/net/http/http_response_info.cc
@@ -81,6 +81,10 @@ enum {
   // This bit is set if the response info has protocol version.
   RESPONSE_INFO_HAS_NPN_NEGOTIATED_PROTOCOL = 1 << 17,
 
+  // This bit is set if the request was overriden from cache due to
+  // various load flags being set.
+  RESPONSE_INFO_WAS_CACHE_OVERRIDE = 1 << 18,

[rvargas (doing something else), 2013/03/05 02:58:19]

This enum is for storing info about this response on the storage, i.e. for stuff
that tells us something about what we have stored in the cache (as opposed to a
property of how we are fulfilling a request).

[Randy Smith (Not in Mondays), 2013/03/05 23:16:14]

The enum was used for pickling and unpickling.  If you're sure we'll never need
to get this info from an HttpResponseInfo that's been persisted, I'll yank out
references to the enum; it just seems weird to me for a bit not to survive
persisting.

[rvargas (doing something else), 2013/03/06 03:11:48]

But we don't really want to persist this flag. That would mean that after
returning content from from the cache (offline), the entry would change on disk
saying that the flag was set... and we would be reading that flag again later.

[Randy Smith (Not in Mondays), 2013/03/06 22:55:55]

Done.

+
   // TODO(darin): Add other bits to indicate alternate request methods.
   // For now, we don't support storing those.
 };
@@ -89,7 +93,8 @@ HttpResponseInfo::HttpResponseInfo()
     : was_cached(false),
       was_fetched_via_spdy(false),
       was_npn_negotiated(false),
-      was_fetched_via_proxy(false) {
+      was_fetched_via_proxy(false),
+      was_cache_override(false) {
 }
 
 HttpResponseInfo::HttpResponseInfo(const HttpResponseInfo& rhs)
@@ -97,6 +102,7 @@ HttpResponseInfo::HttpResponseInfo(const HttpResponseInfo& rhs)
       was_fetched_via_spdy(rhs.was_fetched_via_spdy),
       was_npn_negotiated(rhs.was_npn_negotiated),
       was_fetched_via_proxy(rhs.was_fetched_via_proxy),
+      was_cache_override(rhs.was_cache_override),
       socket_address(rhs.socket_address),
       npn_negotiated_protocol(rhs.npn_negotiated_protocol),
       request_time(rhs.request_time),
@@ -117,6 +123,7 @@ HttpResponseInfo& HttpResponseInfo::operator=(const HttpResponseInfo& rhs) {
   was_fetched_via_spdy = rhs.was_fetched_via_spdy;
   was_npn_negotiated = rhs.was_npn_negotiated;
   was_fetched_via_proxy = rhs.was_fetched_via_proxy;
+  was_cache_override = rhs.was_cache_override;
   socket_address = rhs.socket_address;
   npn_negotiated_protocol = rhs.npn_negotiated_protocol;
   request_time = rhs.request_time;
@@ -221,6 +228,8 @@ bool HttpResponseInfo::InitFromPickle(const Pickle& pickle,
 
   was_fetched_via_proxy = (flags & RESPONSE_INFO_WAS_PROXY) != 0;
 
+  was_cache_override = (flags & RESPONSE_INFO_WAS_CACHE_OVERRIDE) != 0;
+
   *response_truncated = (flags & RESPONSE_INFO_TRUNCATED) != 0;
 
   return true;
@@ -250,6 +259,8 @@ void HttpResponseInfo::Persist(Pickle* pickle,
   }
   if (was_fetched_via_proxy)
     flags |= RESPONSE_INFO_WAS_PROXY;
+  if (was_cache_override)
+    flags |= RESPONSE_INFO_WAS_CACHE_OVERRIDE;
 
   pickle->WriteInt(flags);
   pickle->WriteInt64(request_time.ToInternalValue());