AssetManager2: Implement IDMAP support

This enables RRO (runtime resource overlays) with AssetManager2

Test: make libandroidfw_tests
Test: out/host/<platform>/nativetest64/libandroidfw_tests/libandroidfw_tests --testdata=frameworks/base/libs/androidfw/tests/data
Change-Id: Id8079104faefbfaa3f4017d8f7ee1a8968f151a2
diff --git a/libs/androidfw/Android.bp b/libs/androidfw/Android.bp
index 987096f..5484cf0 100644
--- a/libs/androidfw/Android.bp
+++ b/libs/androidfw/Android.bp
@@ -43,6 +43,7 @@
         "AssetManager2.cpp",
         "AttributeResolution.cpp",
         "ChunkIterator.cpp",
+        "Idmap.cpp",
         "LoadedArsc.cpp",
         "LocaleData.cpp",
         "misc.cpp",