AAPT: Add support for 'font' resource type

Change-Id: I5bc459e34715779ab3b1c415f40f592a4ccbb96e
Test: manual
diff --git a/tools/aapt/Resource.cpp b/tools/aapt/Resource.cpp
index 75a3160..045d68c 100644
--- a/tools/aapt/Resource.cpp
+++ b/tools/aapt/Resource.cpp
@@ -211,7 +211,7 @@
 bool isValidResourceType(const String8& type)
 {
     return type == "anim" || type == "animator" || type == "interpolator"
-        || type == "transition"
+        || type == "transition" || type == "font"
         || type == "drawable" || type == "layout"
         || type == "values" || type == "xml" || type == "raw"
         || type == "color" || type == "menu" || type == "mipmap";