Track constant InputDeviceCapabilities objects per-window.

third_party/WebKit/Source/core/frame/DOMWindow.h

Index: third_party/WebKit/Source/core/frame/DOMWindow.h
diff --git a/third_party/WebKit/Source/core/frame/DOMWindow.h b/third_party/WebKit/Source/core/frame/DOMWindow.h
index dfd491f5e92b85df9c9891727dde2eb126ca5446..c1d2bb8c4a0a4a3e076c767f0820d96a5104cfbd 100644
--- a/third_party/WebKit/Source/core/frame/DOMWindow.h
+++ b/third_party/WebKit/Source/core/frame/DOMWindow.h
@@ -17,6 +17,7 @@
 namespace blink {
 
 class Document;
+class InputDeviceCapabilitiesConstants;
 class Location;
 class LocalDOMWindow;
 class MessageEvent;
@@ -101,6 +102,8 @@ class CORE_EXPORT DOMWindow : public EventTargetWithInlineData,
 
   bool isSecureContext() const;
 
+  InputDeviceCapabilitiesConstants* getInputDeviceCapabilities();
+
  protected:
   explicit DOMWindow(Frame&);
 
@@ -112,6 +115,7 @@ class CORE_EXPORT DOMWindow : public EventTargetWithInlineData,
 
  private:
   Member<Frame> m_frame;
+  Member<InputDeviceCapabilitiesConstants> m_inputCapabilities;
   mutable Member<Location> m_location;
 
   // Set to true when close() has been called. Needed for