Remove unnecessary includes in src/pdf/

src/pdf/SkPDFGraphicState.h

 /*
  * Copyright 2010 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkPDFGraphicState_DEFINED
 #define SkPDFGraphicState_DEFINED
 
-#include "SkPaint.h"
 #include "SkPDFStream.h"
 #include "SkChecksum.h"
 
+class SkPaint;
 class SkPDFCanon;
 class SkPDFFormXObject;
 
 /** \class SkPDFGraphicState
     SkPaint objects roughly correspond to graphic state dictionaries that can
     be installed. So that a given dictionary is only output to the pdf file
     once, we want to canonicalize them.
 */
 class SkPDFGraphicState final : public SkPDFObject {
 
@@ skipping 47 matching lines @@
     const uint8_t fStrokeCap;   // SkPaint::Cap
     const uint8_t fStrokeJoin;  // SkPaint::Join
     const uint8_t fMode;        // SkXfermode::Mode
 
     SkPDFGraphicState(const SkPaint&);
 
     typedef SkPDFDict INHERITED;
 };
 
 #endif