Move the event attach/detach logic on unload from event.js to

extensions/renderer/native_handler.cc

Index: extensions/renderer/native_handler.cc
diff --git a/extensions/renderer/native_handler.cc b/extensions/renderer/native_handler.cc
index 896ef568e1e2b9dfca64a63d9725d27d4d2e9b6f..1fb914fa373acc044218d85be2ea933b651290a6 100644
--- a/extensions/renderer/native_handler.cc
+++ b/extensions/renderer/native_handler.cc
@@ -4,12 +4,20 @@
 
 #include "extensions/renderer/native_handler.h"
 
+#include "base/logging.h"
+
 namespace extensions {
 
 NativeHandler::NativeHandler() : is_valid_(true) {}
 
-NativeHandler::~NativeHandler() {}
+NativeHandler::~NativeHandler() {
+  if (is_valid_)
+    Invalidate();

[Devlin, 2015/04/10 18:25:50]

In retrospect, this won't work.  When a class is destroyed, it loses it's
v-table, so calling Invalidate() here is only ever going to call
NativeHandler::Invalidate(), not, e.g., ModuleSystem::Invalidate().

[not at google - send to devlin, 2015/04/10 19:21:54]

Fixed, though moot.

+}
 
-void NativeHandler::Invalidate() { is_valid_ = false; }
+void NativeHandler::Invalidate() {
+  CHECK(is_valid_);
+  is_valid_ = false;
+}
 
 }  // namespace extensions