SkRemote: add xfermodes

src/core/SkRemote_protocol.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkRemote_protocol_DEFINED
 #define SkRemote_protocol_DEFINED
 
 // ATTENTION!  Changes to this file can break protocol compatibility.  Tread carefully.
 
 namespace SkRemote {
 
     // It is safe to append to this enum without breaking protocol compatibility.
     // Resorting, deleting, or inserting anywhere but the end will break compatibility.
     enum class Type : uint8_t {
         kNone,
 
         kMatrix,
         kMisc,
         kPath,
         kStroke,
+        kXfermode,
     };
 
     class ID {
     public:
         explicit ID(Type type = Type::kNone) : fVal((uint64_t)type << 56) {}
         ID(Type type, uint64_t val) {
             fVal = (uint64_t)type << 56 | val;
             SkASSERT(this->type() == type && this->val() == val);
         }
 
         Type    type() const { return (Type)(fVal >> 56); }
         uint64_t val() const { return fVal & ~((uint64_t)0xFF << 56); }
 
         bool operator==(ID o) const { return fVal == o.fVal; }
-        ID operator++(int) {
-            ID prev = *this;
-            fVal++;
+        ID operator++() {
+            ++fVal;
             SkASSERT(this->val() != 0);  // Overflow is particularly bad as it'd change our Type.
-            return prev;
+            return *this;
         }
 
     private:
         // High 8 bits hold a Type.  Low 56 bits are unique within that Type.
         // Any change to this format will break protocol compatibility.
         uint64_t fVal;
     };
 
 }  // namespace SkRemote
 
 #endif//SkRemote_protocol_DEFINED