Include scaler context flags (gamma and contrast boost) in the text blob cache key.

src/gpu/text/GrAtlasTextBlob.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 GrAtlasTextBlob_DEFINED
 #define GrAtlasTextBlob_DEFINED
 
@@ skipping 43 matching lines @@
         }
         uint32_t fUniqueID;
         // Color may affect the gamma of the mask we generate, but in a fairly limited way.
         // Each color is assigned to on of a fixed number of buckets based on its
         // luminance. For each luminance bucket there is a "canonical color" that
         // represents the bucket.  This functionality is currently only supported for A8
         SkColor fCanonicalColor;
         SkPaint::Style fStyle;
         SkPixelGeometry fPixelGeometry;
         bool fHasBlur;
+        uint32_t fScalerContextFlags;
 
         bool operator==(const Key& other) const {
             return 0 == memcmp(this, &other, sizeof(Key));
         }
     };
 
     void setupKey(const GrAtlasTextBlob::Key& key,
                   const SkMaskFilter::BlurRec& blurRec,
                   const SkPaint& paint) {
         fKey = key;
@@ skipping 475 matching lines @@
     // We can reuse distance field text, but only if the new viewmatrix would not result in
     // a mip change.  Because there can be multiple runs in a blob, we track the overall
     // maximum minimum scale, and minimum maximum scale, we can support before we need to regen
     SkScalar fMaxMinScale;
     SkScalar fMinMaxScale;
     int fRunCount;
     uint8_t fTextType;
 };
 
 #endif