Use uint16s for texture coordinates when rendering text.

src/gpu/GrFontAtlasSizes.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 GrFontAtlasSizes_DEFINED
+#define GrFontAtlasSizes_DEFINED
+
+#define GR_FONT_ATLAS_TEXTURE_WIDTH  1024
+#define GR_FONT_ATLAS_TEXTURE_HEIGHT 2048
+
+#define GR_FONT_ATLAS_PLOT_WIDTH     256
+#define GR_FONT_ATLAS_PLOT_HEIGHT    256
+
+#define GR_FONT_ATLAS_NUM_PLOTS_X   (GR_FONT_ATLAS_TEXTURE_WIDTH / GR_FONT_ATLAS_PLOT_WIDTH)
+#define GR_FONT_ATLAS_NUM_PLOTS_Y   (GR_FONT_ATLAS_TEXTURE_HEIGHT / GR_FONT_ATLAS_PLOT_HEIGHT)
+
+// one over width and height
+#define GR_FONT_ATLAS_RECIP_WIDTH    "0.0009765625"
+#define GR_FONT_ATLAS_RECIP_HEIGHT   "0.00048828125"
+
+// 1/(3*width)
+#define GR_FONT_ATLAS_LCD_DELTA      "0.00032552083"
+
+#endif