Allocate only the vertices we need for text.

src/gpu/GrTextContext.h

 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrTextContext_DEFINED
 #define GrTextContext_DEFINED
 
@@ skipping 39 matching lines @@
                             SkScalar x, SkScalar y) = 0;
     virtual void onDrawPosText(const GrPaint&, const SkPaint&,
                                const char text[], size_t byteLength,
                                const SkScalar pos[], int scalarsPerPosition,
                                const SkPoint& offset) = 0;
 
     void init(const GrPaint&, const SkPaint&);
     void finish() { fDrawTarget = NULL; }
 
     static GrFontScaler* GetGrFontScaler(SkGlyphCache* cache);
-    static void MeasureText(SkGlyphCache* cache, SkDrawCacheProc glyphCacheProc,
-                            const char text[], size_t byteLength, SkVector* stopVector);
+    // sets extent in stopVector and returns glyph count
+    static int MeasureText(SkGlyphCache* cache, SkDrawCacheProc glyphCacheProc,
+                           const char text[], size_t byteLength, SkVector* stopVector);
 };
 
 #endif