Move DistanceAdjustTable to its own file

src/gpu/GrDistanceFieldAdjustTable.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 GrDistanceFieldAdjustTable_DEFINED
+#define GrDistanceFieldAdjustTable_DEFINED
+
+#include "SkRefCnt.h"
+#include "SkScalar.h"
+
+// Distance field text needs this table to compute a value for use in the fragment shader.
+// Because the GrAtlasTextContext can go out of scope before the final flush, this needs to be
+// refcnted and malloced
+struct GrDistanceFieldAdjustTable : public SkNVRefCnt<GrDistanceFieldAdjustTable> {
+    GrDistanceFieldAdjustTable() { this->buildDistanceAdjustTable(); }
+    ~GrDistanceFieldAdjustTable() { delete[] fTable; }
+
+    const SkScalar& operator[] (int i) const {
+        return fTable[i];
+    }
+
+private:
+    void buildDistanceAdjustTable();
+
+    SkScalar* fTable;
+};
+
+#endif