Remove the webkit prefix from idl properties and interfaces.

sky/engine/core/core.gni

Index: sky/engine/core/core.gni
diff --git a/sky/engine/core/core.gni b/sky/engine/core/core.gni
index 5efe2207d179fbc53e3f7587962640bb971ec00b..56cfa646797d8c3b575f85e1fb48e362e99c18d7 100644
--- a/sky/engine/core/core.gni
+++ b/sky/engine/core/core.gni
@@ -675,8 +675,8 @@ sky_core_files = [
   "events/TreeScopeEventContext.h",
   "events/UIEvent.cpp",
   "events/UIEventWithKeyState.cpp",
-  "events/WebKitAnimationEvent.cpp",
-  "events/WebKitAnimationEvent.h",
+  "events/AnimationEvent.cpp",
+  "events/AnimationEvent.h",
   "events/WheelEvent.cpp",
   "events/WheelEvent.h",
   "events/WindowEventContext.cpp",
@@ -1249,10 +1249,10 @@ core_idl_files = get_path_info([
   "css/StyleMedia.idl",
   "css/StyleSheet.idl",
   "css/StyleSheetList.idl",
-  "css/WebKitCSSFilterRule.idl",
-  "css/WebKitCSSFilterValue.idl",
-  "css/WebKitCSSMatrix.idl",
-  "css/WebKitCSSTransformValue.idl",
+  "css/CSSFilterRule.idl",
+  "css/CSSFilterValue.idl",
+  "css/CSSMatrix.idl",
+  "css/CSSTransformValue.idl",
   "dom/Attr.idl",
   "dom/CharacterData.idl",
   "dom/ClientRect.idl",
@@ -1298,7 +1298,7 @@ core_idl_files = get_path_info([
   "events/TouchEvent.idl",
   "events/TransitionEvent.idl",
   "events/UIEvent.idl",
-  "events/WebKitAnimationEvent.idl",
+  "events/AnimationEvent.idl",
   "events/WheelEvent.idl",
   "frame/Console.idl",
   "frame/ConsoleBase.idl",
@@ -1416,7 +1416,7 @@ core_event_idl_files = get_path_info([
   "events/TouchEvent.idl",
   "events/TransitionEvent.idl",
   "events/UIEvent.idl",
-  "events/WebKitAnimationEvent.idl",
+  "events/AnimationEvent.idl",
   "events/WheelEvent.idl",
   "html/MediaKeyEvent.idl",
   "html/canvas/WebGLContextEvent.idl",