Speculative workaround for a crash. Not sure how it could reach this state, b...

chrome/browser/net/passive_log_collector.cc

Index: chrome/browser/net/passive_log_collector.cc
===================================================================
--- chrome/browser/net/passive_log_collector.cc	(revision 50149)
+++ chrome/browser/net/passive_log_collector.cc	(working copy)
@@ -181,7 +181,11 @@
 void PassiveLogCollector::SourceTracker::DeleteSourceInfo(
     uint32 source_id) {
   SourceIDToInfoMap::iterator it = sources_.find(source_id);
-  DCHECK(it != sources_.end());
+  if (it == sources_.end()) {
+    // TODO(eroman): Is this happening? And if so, why.
+    LOG(WARNING) << "Tried to delete info for nonexistent source";
+    return;
+  }
   // The source should not be in the deletion queue.
   DCHECK(std::find(deletion_queue_.begin(), deletion_queue_.end(),
                    source_id) == deletion_queue_.end());