Clean up a few includes, introduce iwyu.

include/ports/SkRemotableFontMgr.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkRemotableFontMgr_DEFINED
 #define SkRemotableFontMgr_DEFINED
 
 #include "SkFontStyle.h"
 #include "SkRefCnt.h"
 #include "SkTemplates.h"
+#include "SkTypes.h"
 
 class SkDataTable;
 class SkStreamAsset;
-class SkString;
 
 struct SK_API SkFontIdentity {
     static const uint32_t kInvalidDataId = 0xFFFFFFFF;
 
     // Note that fDataId is a data identifier, not a font identifier.
     // (fDataID, fTtcIndex) can be seen as a font identifier.
     uint32_t fDataId;
     uint32_t fTtcIndex;
 
     // On Linux/FontConfig there is also the ability to specify preferences for rendering
@@ skipping 117 matching lines @@
      *
      *  The caller must unref() the returned object.
      */
     virtual SkStreamAsset* getData(int dataId) const = 0;
 
 private:
     typedef SkRefCnt INHERITED;
 };
 
 #endif