extensions: Make sure a valid key is used to track the event-listener counts.

extensions/renderer/event_bindings.cc

Index: extensions/renderer/event_bindings.cc
diff --git a/extensions/renderer/event_bindings.cc b/extensions/renderer/event_bindings.cc
index 385906c33989dcbf508b716b1f9f707a5a81fe9a..bad6a02542c6d7c49943f0c6e0718015ae5f0a2f 100644
--- a/extensions/renderer/event_bindings.cc
+++ b/extensions/renderer/event_bindings.cc
@@ -13,6 +13,7 @@
 #include "base/bind.h"
 #include "base/lazy_instance.h"
 #include "base/memory/scoped_ptr.h"
+#include "components/crx_file/id_util.h"
 #include "content/public/renderer/render_thread.h"
 #include "content/public/renderer/render_view.h"
 #include "content/public/renderer/v8_value_converter.h"
@@ -53,6 +54,31 @@ base::LazyInstance<std::map<std::string, FilteredEventListenerCounts> >
 
 base::LazyInstance<EventFilter> g_event_filter = LAZY_INSTANCE_INITIALIZER;
 
+std::string GetKeyForScriptContext(ScriptContext* script_context) {
+  const std::string& extension_id = script_context->GetExtensionID();
+  CHECK(crx_file::id_util::IdIsValid(extension_id) ||
+        script_context->GetURL().is_valid());
+  return crx_file::id_util::IdIsValid(extension_id)
+             ? extension_id
+             : script_context->GetURL().spec();
+}
+
+// Increments the number of event-listeners for the given |event_name| and
+// ScriptContext. Returns the count after the increment.
+int IncrementEventListenerCount(ScriptContext* script_context,
+                                const std::string& event_name) {
+  return ++g_listener_counts
+               .Get()[GetKeyForScriptContext(script_context)][event_name];
+}
+
+// Decrements the number of event-listeners for the given |event_name| and
+// ScriptContext. Returns the count after the increment.
+int DecrementEventListenerCount(ScriptContext* script_context,
+                                const std::string& event_name) {
+  return --g_listener_counts
+               .Get()[GetKeyForScriptContext(script_context)][event_name];
+}
+
 bool IsLazyBackgroundPage(content::RenderView* render_view,
                           const Extension* extension) {
   if (!render_view)
@@ -147,9 +173,8 @@ void EventBindings::AttachEvent(
   if (!dispatcher_->CheckContextAccessToExtensionAPI(event_name, context()))
     return;
 
-  std::string extension_id = context()->GetExtensionID();
-  EventListenerCounts& listener_counts = g_listener_counts.Get()[extension_id];
-  if (++listener_counts[event_name] == 1) {
+  const std::string& extension_id = context()->GetExtensionID();
+  if (IncrementEventListenerCount(context(), event_name) == 1) {
     content::RenderThread::Get()->Send(new ExtensionHostMsg_AddListener(
         extension_id, context()->GetURL(), event_name));
   }
@@ -173,10 +198,8 @@ void EventBindings::DetachEvent(
   std::string event_name = *v8::String::Utf8Value(args[0]);
   bool is_manual = args[1]->BooleanValue();
 
-  std::string extension_id = context()->GetExtensionID();
-  EventListenerCounts& listener_counts = g_listener_counts.Get()[extension_id];
-
-  if (--listener_counts[event_name] == 0) {
+  const std::string& extension_id = context()->GetExtensionID();
+  if (DecrementEventListenerCount(context(), event_name) == 0) {
     content::RenderThread::Get()->Send(new ExtensionHostMsg_RemoveListener(
         extension_id, context()->GetURL(), event_name));
   }