Add support for caching font files in the Android SkFontMgr.

src/ports/SkFontMgr_android_factory.cpp

Index: src/ports/SkFontMgr_android_factory.cpp
diff --git a/src/ports/SkFontMgr_android_factory.cpp b/src/ports/SkFontMgr_android_factory.cpp
index 99f654d838590d49b1272d89c953a5b9e8b57f5f..ce39b2cf97df5d89b4bf5fee137d5d0e4880af18 100644
--- a/src/ports/SkFontMgr_android_factory.cpp
+++ b/src/ports/SkFontMgr_android_factory.cpp
@@ -36,7 +36,8 @@ SkFontMgr* SkFontMgr::Factory() {
             SkFontMgr_Android_CustomFonts::kOnlyCustom,
             gTestBasePath,
             gTestFontsXml,
-            gTestFallbackFontsXml
+            gTestFallbackFontsXml,
+            false /* fIsolated */
         };
         return SkFontMgr_New_Android(&custom);
     }