when we disable lcd for impl reasons, add kGenA8 to document the original intent

include/core/SkDevice.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 SkDevice_DEFINED
 #define SkDevice_DEFINED
 
@@ skipping 120 matching lines @@
 #endif
     };
 
 protected:
     enum Usage {
        kGeneral_Usage,
        kSaveLayer_Usage  // <! internal use only
     };
 
     struct TextFlags {
-        uint32_t            fFlags;     // SkPaint::getFlags()
-        SkPaint::Hinting    fHinting;
+        uint32_t    fFlags;     // SkPaint::getFlags()
     };
 
     /**
      *  Device may filter the text flags for drawing text here. If it wants to
      *  make a change to the specified values, it should write them into the
      *  textflags parameter (output) and return true. If the paint is fine as
      *  is, then ignore the textflags parameter and return false.
      */
     virtual bool filterTextFlags(const SkPaint& paint, TextFlags*) { return false; }
 
@@ skipping 240 matching lines @@
     SkMetaData* fMetaData;
 
 #ifdef SK_DEBUG
     bool        fAttachedToCanvas;
 #endif
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif