AAPT2: Support CtsContentTestCases build

- Add <feature-group> to ManifestFixer.
- Support <meta-data> in <instrumentation>
- Add support for <bag> and type="configVarying". Some CTS tests use this
  old notation, we need to support it (even though configVarying isn't
  anything supported by the framework convention).

Change-Id: I6946fa633ce513ea8437c1496db883cf27dcf6de
Test: make aapt2_tests
diff --git a/tools/aapt2/ResourceParser.h b/tools/aapt2/ResourceParser.h
index c12dacf..cc0fa26 100644
--- a/tools/aapt2/ResourceParser.h
+++ b/tools/aapt2/ResourceParser.h
@@ -102,7 +102,8 @@
                      bool weak);
   Maybe<Attribute::Symbol> ParseEnumOrFlagItem(xml::XmlPullParser* parser,
                                                const android::StringPiece& tag);
-  bool ParseStyle(xml::XmlPullParser* parser, ParsedResource* out_resource);
+  bool ParseStyle(const ResourceType type, xml::XmlPullParser* parser,
+                  ParsedResource* out_resource);
   bool ParseStyleItem(xml::XmlPullParser* parser, Style* style);
   bool ParseDeclareStyleable(xml::XmlPullParser* parser,
                              ParsedResource* out_resource);