Assert that thread-safe reference counting is used with

cross-thread NewRunnableMethod.

This assertion caught such an error in VisitedLinkMaster!

My approach, modify RunnableMethodTraits<T> to assert that
when ReleaseCallee happens on a different thread from
RetainCallee that the type supports thread-safe reference
counting.  I do this by adding a static method to both
RefCounted<T> and RefCountedThreadSafe<T>.

This results in a little ugliness in cases where people
implement AddRef and Release by hand (to make the no-ops).
There may be a nicer way to deal with those few cases.

R=brettw
BUG=none
TEST=none

Review URL: http://codereview.chromium.org/251012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@27379 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 6 insertions, 9 deletions

diff --git a/chrome/browser/browsing_data_remover.cc b/chrome/browser/browsing_data_remover.cc
index 96e1543..6d70cc9 100644
--- a/chrome/browser/browsing_data_remover.cc
+++ b/chrome/browser/browsing_data_remover.cc
@@ -22,16 +22,13 @@
 #include "net/url_request/url_request_context.h"
 #include "webkit/glue/password_form.h"
 
-// Done so that we can use invokeLater on BrowsingDataRemovers and not have
+// Done so that we can use PostTask on BrowsingDataRemovers and not have
 // BrowsingDataRemover implement RefCounted.
-template<>
-void RunnableMethodTraits<BrowsingDataRemover>::RetainCallee(
-    BrowsingDataRemover* remover) {
-}
-template<>
-void RunnableMethodTraits<BrowsingDataRemover>::ReleaseCallee(
-    BrowsingDataRemover* remover) {
-}
+template <>
+struct RunnableMethodTraits<BrowsingDataRemover> {
+  void RetainCallee(BrowsingDataRemover*) {}
+  void ReleaseCallee(BrowsingDataRemover*) {}
+};
 
 bool BrowsingDataRemover::removing_ = false;