Fix autofill popup controller key press callback registration

components/autofill/content/browser/key_press_handler_manager.cc

Index: components/autofill/content/browser/key_press_handler_manager.cc
diff --git a/components/autofill/content/browser/key_press_handler_manager.cc b/components/autofill/content/browser/key_press_handler_manager.cc
new file mode 100644
index 0000000000000000000000000000000000000000..96b463bc5d4e1b6dc277540e96fdc4e67fcad5e7
--- /dev/null
+++ b/components/autofill/content/browser/key_press_handler_manager.cc
@@ -0,0 +1,37 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/autofill/content/browser/key_press_handler_manager.h"
+
+namespace autofill {
+
+KeyPressHandlerManager::KeyPressHandlerManager(Delegate* delegate)
+    : delegate_(delegate) {}
+
+KeyPressHandlerManager::~KeyPressHandlerManager() = default;
+
+void KeyPressHandlerManager::RegisterKeyPressHandler(
+    const content::RenderWidgetHost::KeyPressEventCallback& handler) {
+  // It would have been nice to be able to tell if two callbacks are just the
+  // same function with the same bound arguments. That's not what Equals() does
+  // (they have to have the same BindState), but it's the closest approximation
+  // available.
+  if (handler.is_null() || handler.Equals(handler_))
+    return;
+
+  if (!handler_.is_null())
+    delegate_->RemoveHandler(handler_);
+  handler_ = handler;
+  delegate_->AddHandler(handler_);
+}
+
+void KeyPressHandlerManager::RemoveKeyPressHandler() {
+  if (handler_.is_null())
+    return;
+
+  delegate_->RemoveHandler(handler_);
+  handler_.Reset();
+}
+
+}  // namespace autofill