Remove PlatformEvent it is no longer used.

third_party/WebKit/Source/core/events/KeyboardEvent.cpp

Index: third_party/WebKit/Source/core/events/KeyboardEvent.cpp
diff --git a/third_party/WebKit/Source/core/events/KeyboardEvent.cpp b/third_party/WebKit/Source/core/events/KeyboardEvent.cpp
index e7581e89641e43fe8bd7ffc3d7428ece99f9be6b..806a2403fdcc27f114dc5517e9738457a82b977b 100644
--- a/third_party/WebKit/Source/core/events/KeyboardEvent.cpp
+++ b/third_party/WebKit/Source/core/events/KeyboardEvent.cpp
@@ -95,7 +95,7 @@ KeyboardEvent::KeyboardEvent(const WebKeyboardEvent& key,
           true,
           domWindow,
           0,
-          static_cast<PlatformEvent::Modifiers>(key.modifiers()),
+          static_cast<WebInputEvent::Modifiers>(key.modifiers()),
           TimeTicks::FromSeconds(key.timeStampSeconds()),
           domWindow
               ? domWindow->getInputDeviceCapabilities()->firesTouchEvents(false)
@@ -117,7 +117,7 @@ KeyboardEvent::KeyboardEvent(const AtomicString& eventType,
       m_location(initializer.location()),
       m_isComposing(initializer.isComposing()) {
   if (initializer.repeat())
-    m_modifiers |= PlatformEvent::IsAutoRepeat;
+    m_modifiers |= WebInputEvent::IsAutoRepeat;
   initLocationModifiers(initializer.location());
 }
 
@@ -196,13 +196,13 @@ int KeyboardEvent::which() const {
 void KeyboardEvent::initLocationModifiers(unsigned location) {
   switch (location) {
     case KeyboardEvent::kDomKeyLocationNumpad:
-      m_modifiers |= PlatformEvent::IsKeyPad;
+      m_modifiers |= WebInputEvent::IsKeyPad;
       break;
     case KeyboardEvent::kDomKeyLocationLeft:
-      m_modifiers |= PlatformEvent::IsLeft;
+      m_modifiers |= WebInputEvent::IsLeft;
       break;
     case KeyboardEvent::kDomKeyLocationRight:
-      m_modifiers |= PlatformEvent::IsRight;
+      m_modifiers |= WebInputEvent::IsRight;
       break;
   }
 }