Stay in floats as much as possible in SkTileGrid, particularly in insert.

src/core/SkTileGrid.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkTileGrid_DEFINED
 #define SkTileGrid_DEFINED
 
@@ skipping 24 matching lines @@
     /**
      * Populate 'results' with opIndexes corresponding to bounding boxes that intersect 'query'.
      * This will be fastest if the query is an exact match to a single grid tile.
      */
     virtual void search(const SkRect& query, SkTDArray<unsigned>* results) const SK_OVERRIDE;
 
     // For testing.
     int tileCount(int x, int y) { return fTiles[y * fXTiles + x].count(); }
 
 private:
+    void commonAdjust(SkRect*) const;
+    void userToGrid(const SkRect&, SkIRect* grid) const;
+
     const int fXTiles, fYTiles;
-    SkTileGridFactory::TileGridInfo fInfo;
+    const SkScalar fInvWidth, fInvHeight;
+    const SkScalar fMarginWidth, fMarginHeight;
+    const SkPoint fOffset;
+    const SkRect  fGridBounds;
 
     // (fXTiles * fYTiles) SkTDArrays, each listing ops overlapping that tile in order.
     SkTDArray<unsigned>* fTiles;
 
     typedef SkBBoxHierarchy INHERITED;
 };
 
 #endif