base::RefCounted now DCHECKs when referenced from multiple threads.

extensions/browser/api/cast_channel/logger.h

Index: extensions/browser/api/cast_channel/logger.h
diff --git a/extensions/browser/api/cast_channel/logger.h b/extensions/browser/api/cast_channel/logger.h
index e6462bb74b3c2b8b4b381deba625b040d0dc2858..3fe4a7a56aecfbf5bd7a9eefc30f19804de62c61 100644
--- a/extensions/browser/api/cast_channel/logger.h
+++ b/extensions/browser/api/cast_channel/logger.h
@@ -33,7 +33,8 @@ static const int kMaxEventsPerSocket = 2000;
 
 // Logs information of each channel and sockets and exports the log as
 // a blob. Logger is done on the IO thread.
-class Logger : public base::RefCounted<Logger> {
+// TODO(mgiuca): Avoid using UnsafeRefCounted. http://crbug.com/469952.
+class Logger : public base::UnsafeRefCounted<Logger> {
  public:
   // |clock|: Clock used for generating timestamps for the events. Owned by
   // this class.
@@ -87,7 +88,7 @@ class Logger : public base::RefCounted<Logger> {
   LastErrors GetLastErrors(int channel_id) const;
 
  private:
-  friend class base::RefCounted<Logger>;
+  friend class base::UnsafeRefCounted<Logger>;
   ~Logger();
 
   struct AggregatedSocketEventLog {