Use puts() instead of pluginLog() to avoid running JS during detach.

content/shell/tools/plugin/main.cpp

Index: content/shell/tools/plugin/main.cpp
diff --git a/content/shell/tools/plugin/main.cpp b/content/shell/tools/plugin/main.cpp
index 6cfab1c41011755ff5c7bb0076a93b1a30a19675..ed1fb3c18b6c8a80b51f4137cec85b9aced410ea 100644
--- a/content/shell/tools/plugin/main.cpp
+++ b/content/shell/tools/plugin/main.cpp
@@ -348,8 +348,11 @@ NPError NPP_Destroy(NPP instance, NPSavedData **save)
         if (obj->evaluateScriptOnMouseDownOrKeyDown)
             free(obj->evaluateScriptOnMouseDownOrKeyDown);
 
-        if (obj->logDestroy)
-            pluginLog(instance, "NPP_Destroy");
+        if (obj->logDestroy) {
+            // Note: this intentionally avoids using pluginLog(), because that
+            // requires running JS during document detach, which is forbidden.
+            puts("PLUGIN: NPP_Destroy");
+        }
 
 #ifdef XP_MACOSX
         if (obj->coreAnimationLayer)