up glyphcache hash table to 12bits (from 8bits).

Experimenting shows that is the sweetspot when drawing lots of CJK



git-svn-id: http://skia.googlecode.com/svn/trunk@2582 2bbb7eff-a529-9590-31e7-b0007b416f81

src/core/SkGlyphCache.h

@@ -220,7 +220,7 @@ private:
     SkPaint::FontMetrics fFontMetricsY;
 
     enum {
-        kHashBits   = 8,
+        kHashBits   = 12,
         kHashCount  = 1 << kHashBits,
         kHashMask   = kHashCount - 1
     };