Bypass http cache for concurrent range requests.

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 286a526a3edb2fa39e7101e10429cf3c15b7920a..5436ff4cef507e824a34e283833e853b9776d3cb 100644
--- a/net/http/http_cache_transaction.cc
+++ b/net/http/http_cache_transaction.cc
@@ -1382,7 +1382,20 @@ int HttpCache::Transaction::DoAddToEntry() {
     if (bypass_lock_for_test_) {
       OnAddToEntryTimeout(entry_lock_waiting_since_);
     } else {
-      const int kTimeoutSeconds = 20;
+      // Immediately timeout and bypass the cache if we're a range request and
+      // we're blocked by the reader/writer lock. Doing so eliminates a long
+      // running issue, http://crbug.com/31014, where two of the same media
+      // resources could not be played back simultaneously due to one locking
+      // the cache entry until the entire video was downloaded.
+      //
+      // Bypassing the cache is not ideal, as we are now ignoring the cache
+      // entirely for all range requests to a resource beyond the first. This is
+      // however a much more succinct solution than the alternatives, which
+      // would require somewhat significant changes to the http caching logic.
+      const int kTimeoutSeconds = (partial_ && new_entry_->writer &&

[rvargas (doing something else), 2014/08/22 22:19:24]

nit:
      int timeout_seconds = 20;
      if (partial_ && new_entry_->writer &&
          new_entry_->writer->range_requested_) {
        // Immediately bypass the cache for range requests. Doing so...
        timeout_seconds = 0;
      }

[DaleCurtis, 2014/08/22 22:33:03]

Done.

+                                   new_entry_->writer->range_requested_)
+                                      ? 0
+                                      : 20;
       base::MessageLoop::current()->PostDelayedTask(
           FROM_HERE,
           base::Bind(&HttpCache::Transaction::OnAddToEntryTimeout,