Remove SkField, it's no longer used

Bug: skia:
Change-Id: I8efcbb09dce2cb0e4f33a10e4ff2148058c6fbc5
Reviewed-on: https://skia-review.googlesource.com/c/193362
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
diff --git a/modules/particles/include/SkParticleSerialization.h b/modules/particles/include/SkParticleSerialization.h
index a1773fa..c90fbad 100644
--- a/modules/particles/include/SkParticleSerialization.h
+++ b/modules/particles/include/SkParticleSerialization.h
@@ -19,28 +19,28 @@
     SkToJsonVisitor(SkJSONWriter& writer) : fWriter(writer) {}
 
     // Primitives
-    void visit(const char* name, float& f, SkField) override {
+    void visit(const char* name, float& f) override {
         fWriter.appendFloat(name, f);
     }
-    void visit(const char* name, int& i, SkField) override {
+    void visit(const char* name, int& i) override {
         fWriter.appendS32(name, i);
     }
-    void visit(const char* name, bool& b, SkField) override {
+    void visit(const char* name, bool& b) override {
         fWriter.appendBool(name, b);
     }
-    void visit(const char* name, SkString& s, SkField) override {
+    void visit(const char* name, SkString& s) override {
         fWriter.appendString(name, s.c_str());
     }
 
     // Compound types
-    void visit(const char* name, SkPoint& p, SkField) override {
+    void visit(const char* name, SkPoint& p) override {
         fWriter.beginObject(name, false);
         fWriter.appendFloat("x", p.fX);
         fWriter.appendFloat("y", p.fY);
         fWriter.endObject();
     }
 
-    void visit(const char* name, SkColor4f& c, SkField) override {
+    void visit(const char* name, SkColor4f& c) override {
         fWriter.beginArray(name, false);
         fWriter.appendFloat(c.fR);
         fWriter.appendFloat(c.fG);
@@ -75,27 +75,27 @@
         fStack.push_back(&fRoot);
     }
 
-    void visit(const char* name, float& f, SkField) override {
+    void visit(const char* name, float& f) override {
         TryParse(get(name), f);
     }
-    void visit(const char* name, int& i, SkField) override {
+    void visit(const char* name, int& i) override {
         TryParse(get(name), i);
     }
-    void visit(const char* name, bool& b, SkField) override {
+    void visit(const char* name, bool& b) override {
         TryParse(get(name), b);
     }
-    void visit(const char* name, SkString& s, SkField) override {
+    void visit(const char* name, SkString& s) override {
         TryParse(get(name), s);
     }
 
-    void visit(const char* name, SkPoint& p, SkField) override {
+    void visit(const char* name, SkPoint& p) override {
         if (const skjson::ObjectValue* obj = get(name)) {
             TryParse((*obj)["x"], p.fX);
             TryParse((*obj)["y"], p.fY);
         }
     }
 
-    void visit(const char* name, SkColor4f& c, SkField) override {
+    void visit(const char* name, SkColor4f& c) override {
         const skjson::ArrayValue* arr = get(name);
         if (arr && arr->size() == 4) {
             TryParse((*arr)[0], c.fR);