diff --git a/atom/browser/api/event_emitter.h b/atom/browser/api/event_emitter.h
index 5e4ca3b4ffcb1..2ae93b706fa8e 100644
--- a/atom/browser/api/event_emitter.h
+++ b/atom/browser/api/event_emitter.h
@@ -8,6 +8,7 @@
 #include <vector>
 
 #include "atom/common/api/event_emitter_caller.h"
+#include "content/public/browser/browser_thread.h"
 #include "native_mate/wrappable.h"
 
 namespace content {
@@ -97,6 +98,7 @@ class EventEmitter : public Wrappable<T> {
   bool EmitWithEvent(const base::StringPiece& name,
                      v8::Local<v8::Object> event,
                      const Args&... args) {
+    DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
     v8::Locker locker(isolate());
     v8::HandleScope handle_scope(isolate());
     EmitEvent(isolate(), GetWrapper(), name, event, args...);
diff --git a/atom/browser/net/js_asker.cc b/atom/browser/net/js_asker.cc
index 1e3511fc5f606..7b887a6d0f47f 100644
--- a/atom/browser/net/js_asker.cc
+++ b/atom/browser/net/js_asker.cc
@@ -7,6 +7,7 @@
 #include <utility>
 
 #include "atom/common/native_mate_converters/callback.h"
+#include "content/public/browser/browser_thread.h"
 
 namespace atom {
 
diff --git a/atom/common/native_mate_converters/callback.cc b/atom/common/native_mate_converters/callback.cc
index 27d43a0ad8e1a..7a1a855f6a7b2 100644
--- a/atom/common/native_mate_converters/callback.cc
+++ b/atom/common/native_mate_converters/callback.cc
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "atom/common/native_mate_converters/callback.h"
+#include "content/public/browser/browser_thread.h"
 
 #include "native_mate/dictionary.h"
 
diff --git a/atom/common/native_mate_converters/callback.h b/atom/common/native_mate_converters/callback.h
index 5ec1c317a8e9f..3fea5b9f31067 100644
--- a/atom/common/native_mate_converters/callback.h
+++ b/atom/common/native_mate_converters/callback.h
@@ -12,7 +12,6 @@
 #include "base/callback.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
-#include "content/public/browser/browser_thread.h"
 #include "native_mate/function_template.h"
 #include "native_mate/scoped_persistent.h"