Expose the GamepadButton interface object

https://dvcs.w3.org/hg/gamepad/raw-file/default/gamepad.html#gamepadbutton-interface

IE and Firefox already expose this interface object.

Review URL: https://codereview.chromium.org/859503004

git-svn-id: svn://svn.chromium.org/blink/trunk@188694 bbb929c8-8fbe-4397-9dbb-9b2b20218538
diff --git a/third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-expected.txt b/third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-expected.txt
index f5081de..37f5ff5 100644
--- a/third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-expected.txt
+++ b/third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-expected.txt
@@ -651,6 +651,8 @@
     method constructor
 interface Gamepad
     method constructor
+interface GamepadButton
+    method constructor
 interface GamepadEvent
     method constructor
 interface HTMLAllCollection
diff --git a/third_party/WebKit/LayoutTests/webexposed/global-interface-listing-expected.txt b/third_party/WebKit/LayoutTests/webexposed/global-interface-listing-expected.txt
index e994ae0..8f7b265 100644
--- a/third_party/WebKit/LayoutTests/webexposed/global-interface-listing-expected.txt
+++ b/third_party/WebKit/LayoutTests/webexposed/global-interface-listing-expected.txt
@@ -724,6 +724,8 @@
     method constructor
 interface Gamepad
     method constructor
+interface GamepadButton
+    method constructor
 interface GamepadEvent
     method constructor
 interface HTMLAllCollection
diff --git a/third_party/WebKit/Source/modules/gamepad/GamepadButton.idl b/third_party/WebKit/Source/modules/gamepad/GamepadButton.idl
index 19d88ce..1a4a8cb 100644
--- a/third_party/WebKit/Source/modules/gamepad/GamepadButton.idl
+++ b/third_party/WebKit/Source/modules/gamepad/GamepadButton.idl
@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 [
-    NoInterfaceObject,
     GarbageCollected,
 ] interface GamepadButton {
     readonly attribute boolean pressed;