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, 1 insertions, 9 deletions

diff --git a/chrome/browser/printing/printer_query.h b/chrome/browser/printing/printer_query.h
index 6d6fd88..b0502c8 100644
--- a/chrome/browser/printing/printer_query.h
+++ b/chrome/browser/printing/printer_query.h
@@ -6,7 +6,6 @@
 #define CHROME_BROWSER_PRINTING_PRINTER_QUERY_H_
 
 #include "base/scoped_ptr.h"
-#include "base/ref_counted.h"
 #include "chrome/browser/printing/print_job_worker_owner.h"
 
 class CancelableTask;
@@ -21,8 +20,7 @@ namespace printing {
 class PrintJobWorker;
 
 // Query the printer for settings.
-class PrinterQuery : public base::RefCountedThreadSafe<PrinterQuery>,
-                     public PrintJobWorkerOwner {
+class PrinterQuery : public PrintJobWorkerOwner {
  public:
   // GetSettings() UI parameter.
   enum GetSettingsAskParam {
@@ -34,12 +32,6 @@ class PrinterQuery : public base::RefCountedThreadSafe<PrinterQuery>,
   virtual ~PrinterQuery();
 
   // PrintJobWorkerOwner
-  virtual void AddRef() {
-    return base::RefCountedThreadSafe<PrinterQuery>::AddRef();
-  }
-  virtual void Release() {
-    return base::RefCountedThreadSafe<PrinterQuery>::Release();
-  }
   virtual void GetSettingsDone(const PrintSettings& new_settings,
                                PrintingContext::Result result);
   virtual PrintJobWorker* DetachWorker(PrintJobWorkerOwner* new_owner);