use new PurgeFontCache() api



git-svn-id: http://skia.googlecode.com/svn/trunk@2633 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/bench/FontScalerBench.cpp b/bench/FontScalerBench.cpp
index 4255f67..4ac6a35 100644
--- a/bench/FontScalerBench.cpp
+++ b/bench/FontScalerBench.cpp
@@ -37,7 +37,8 @@
 
         // this is critical - we want to time the creation process, so we
         // explicitly flush our cache before each run
-        SkGraphics::SetFontCacheUsed(0);
+        SkGraphics::PurgeFontCache();
+
         for (int ps = 9; ps <= 24; ps += 2) {
             paint.setTextSize(SkIntToScalar(ps));
             canvas->drawText(fText.c_str(), fText.size(),