webRequest: reliably determine tabId

extensions/browser/extension_api_frame_id_map.cc

 // Copyright 2015 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 "extensions/browser/extension_api_frame_id_map.h"
 
 #include <tuple>
 
 #include "base/metrics/histogram_macros.h"
 #include "content/public/browser/browser_thread.h"
@@ skipping 288 matching lines @@
       found = true;
     }
   }
 
   // TODO(devlin): Depending on how the data looks, this may be removable after
   // a few cycles. Check back in M52 to see if it's still needed.
   UMA_HISTOGRAM_BOOLEAN("Extensions.ExtensionFrameMapCacheHit", found);
   return found;
 }
 
+ExtensionApiFrameIdMap::FrameData ExtensionApiFrameIdMap::GetFrameData(
+    content::RenderFrameHost* rfh) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
+  const RenderFrameIdKey key(rfh->GetProcess()->GetID(), rfh->GetRoutingID());
+  return LookupFrameDataOnUI(key, true /* for lookup */);

[Devlin, 2016/05/23 20:28:48]

In retrospect, this was probably a poorly named boolean.  The idea here is that
we're recording how often we find the value for a frame after a cache miss
(indicating the value of performing the thread hop).  Since there was no initial
cache miss here, I'd prefer not to record for this case.  It would probably be
good to also rename the boolean to something like "for_lookup_after_cache_miss"
to make this more clear.

[robwu, 2016/05/23 20:54:15]

Done. for_lookup_after_cache_miss was a bit too long for my like, so I went with
is_from_io instead.

[Devlin, 2016/05/23 20:56:12]

sgtm

+}
+
 void ExtensionApiFrameIdMap::CacheFrameData(content::RenderFrameHost* rfh) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
   const RenderFrameIdKey key(rfh->GetProcess()->GetID(), rfh->GetRoutingID());
   CacheFrameData(key);
   DCHECK(frame_data_map_.find(key) != frame_data_map_.end());
 }
 
 void ExtensionApiFrameIdMap::CacheFrameData(const RenderFrameIdKey& key) {
   LookupFrameDataOnUI(key, false /* not for lookup */);
@@ skipping 26 matching lines @@
 }
 
 void ExtensionApiFrameIdMap::RemoveFrameData(const RenderFrameIdKey& key) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
   base::AutoLock lock(frame_data_map_lock_);
   frame_data_map_.erase(key);
 }
 
 }  // namespace extensions