Add SkDrawPosTextHCommand JSON, fix skiaserve build.

tools/debugger/SkDrawCommand.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SKDRAWCOMMAND_H_
 #define SKDRAWCOMMAND_H_
 
@@ skipping 479 matching lines @@
 
     typedef SkDrawCommand INHERITED;
 };
 
 class SkDrawPosTextHCommand : public SkDrawCommand {
 public:
     SkDrawPosTextHCommand(const void* text, size_t byteLength, const SkScalar xpos[],
                           SkScalar constY, const SkPaint& paint);
     virtual ~SkDrawPosTextHCommand() { delete [] fXpos; delete [] fText; }
     void execute(SkCanvas* canvas) const override;
+    Json::Value toJSON(UrlDataManager& urlDataManager) const override;
+    static SkDrawPosTextHCommand* fromJSON(Json::Value& command, UrlDataManager& urlDataManager);
 
 private:
     SkScalar* fXpos;
     char*     fText;
     size_t    fByteLength;
     SkScalar  fConstY;
     SkPaint   fPaint;
 
     typedef SkDrawCommand INHERITED;
 };
@@ skipping 156 matching lines @@
     static SkSetMatrixCommand* fromJSON(Json::Value& command, UrlDataManager& urlDataManager);
 
 private:
     SkMatrix fUserMatrix;
     SkMatrix fMatrix;
 
     typedef SkDrawCommand INHERITED;
 };
 
 #endif