Delay instantiating InputDeviceCapabilities until accessed.

third_party/WebKit/Source/core/events/MouseEvent.h

Index: third_party/WebKit/Source/core/events/MouseEvent.h
diff --git a/third_party/WebKit/Source/core/events/MouseEvent.h b/third_party/WebKit/Source/core/events/MouseEvent.h
index 831be6c723f3fa9bcb95a19194255f880e305b90..e77103571fc8aa7f869c3c13098f04c46ad9a689 100644
--- a/third_party/WebKit/Source/core/events/MouseEvent.h
+++ b/third_party/WebKit/Source/core/events/MouseEvent.h
@@ -218,20 +218,21 @@ class CORE_EXPORT MouseEvent : public UIEventWithKeyState {
 
  private:
   friend class MouseEventDispatchMediator;
-  void initMouseEventInternal(const AtomicString& type,
-                              bool canBubble,
-                              bool cancelable,
-                              AbstractView*,
-                              int detail,
-                              int screenX,
-                              int screenY,
-                              int clientX,
-                              int clientY,
-                              PlatformEvent::Modifiers,
-                              short button,
-                              EventTarget* relatedTarget,
-                              InputDeviceCapabilities* sourceCapabilities,
-                              unsigned short buttons = 0);
+  void initMouseEventInternal(
+      const AtomicString& type,
+      bool canBubble,
+      bool cancelable,
+      AbstractView*,
+      int detail,
+      int screenX,
+      int screenY,
+      int clientX,
+      int clientY,
+      PlatformEvent::Modifiers,
+      short button,
+      EventTarget* relatedTarget,
+      const InputDeviceCapabilitiesValue& sourceCapabilities,
+      unsigned short buttons = 0);
 
   void initCoordinates(const double clientX, const double clientY);
   void initCoordinatesFromRootFrame(int windowX, int windowY);