Parse input argument types and store the argument types in CSSPaintDefinition.

third_party/WebKit/Source/modules/csspaint/CSSPaintDefinition.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CSSPaintDefinition_h
 #define CSSPaintDefinition_h
 
 #include "bindings/core/v8/ScopedPersistent.h"
 #include "core/CSSPropertyNames.h"
+#include "core/css/CSSSyntaxDescriptor.h"
 #include "platform/geometry/IntSize.h"
 #include "platform/heap/Handle.h"
 #include <v8.h>
 
 namespace blink {
 
 class Image;
 class LayoutObject;
 class ScriptState;
 
 // Represents a javascript class registered on the PaintWorkletGlobalScope by
 // the author.

[ikilpatrick, 2017/01/18 01:32:32]

If you like this comment could be expanded now that this class is growing, an
explanation of the things it holds onto here and what they are used for. 

Or in a follow up patch if you like :)

 class CSSPaintDefinition final
     : public GarbageCollectedFinalized<CSSPaintDefinition> {
  public:
   static CSSPaintDefinition* create(
       ScriptState*,
       v8::Local<v8::Function> constructor,
       v8::Local<v8::Function> paint,
       Vector<CSSPropertyID>&,
       Vector<AtomicString>& customInvalidationProperties,
+      Vector<CSSSyntaxDescriptor>& inputArgumentTypes,
       bool hasAlpha);
   virtual ~CSSPaintDefinition();
 
   // Invokes the javascript 'paint' callback on an instance of the javascript
   // class. The size given will be the size of the PaintRenderingContext2D
   // given to the callback.
   //
   // This may return a nullptr (representing an invalid image) if javascript
   // throws an error.
   PassRefPtr<Image> paint(const LayoutObject&, const IntSize&, float zoom);
   const Vector<CSSPropertyID>& nativeInvalidationProperties() const {
     return m_nativeInvalidationProperties;
   }
   const Vector<AtomicString>& customInvalidationProperties() const {
     return m_customInvalidationProperties;
   }
+  const Vector<CSSSyntaxDescriptor>& inputArgumentTypes() const {
+    return m_inputArgumentTypes;
+  }
   bool hasAlpha() const { return m_hasAlpha; }
 
   ScriptState* getScriptState() const { return m_scriptState.get(); }
 
   v8::Local<v8::Function> paintFunctionForTesting(v8::Isolate* isolate) {
     return m_paint.newLocal(isolate);
   }
 
   DEFINE_INLINE_TRACE(){};
 
  private:
   CSSPaintDefinition(ScriptState*,
                      v8::Local<v8::Function> constructor,
                      v8::Local<v8::Function> paint,
                      Vector<CSSPropertyID>& nativeInvalidationProperties,
                      Vector<AtomicString>& customInvalidationProperties,
+                     Vector<CSSSyntaxDescriptor>& inputArgumentTypes,
                      bool hasAlpha);
 
   void maybeCreatePaintInstance();
 
   RefPtr<ScriptState> m_scriptState;
 
   // This object keeps the class instance object, constructor function and
   // paint function alive. This object needs to be destroyed to break a
   // reference cycle between it and the PaintWorkletGlobalScope.
   ScopedPersistent<v8::Function> m_constructor;
   ScopedPersistent<v8::Function> m_paint;
 
   // At the moment there is only ever one instance of a paint class per type.
   ScopedPersistent<v8::Object> m_instance;
 
   bool m_didCallConstructor;
 
   Vector<CSSPropertyID> m_nativeInvalidationProperties;
   Vector<AtomicString> m_customInvalidationProperties;
+  // Input argument types, if applicable.
+  Vector<CSSSyntaxDescriptor> m_inputArgumentTypes;
   bool m_hasAlpha;
 };
 
 }  // namespace blink
 
 #endif  // CSSPaintDefinition_h