Revert "Remove mediarouter v7 support library from SDK."

This reverts commit 0eacd936b7d6dabd380ecd6f1d25d39625b37495.

Bug: 9425325
Change-Id: Idf81e6721fb4361a38ffd73d39c574c2cb2b1155
diff --git a/core/pathmap.mk b/core/pathmap.mk
index d0339ea..09f912e 100644
--- a/core/pathmap.mk
+++ b/core/pathmap.mk
@@ -114,6 +114,7 @@
         v4 \
         v7/gridlayout \
         v7/appcompat \
+        v7/mediarouter \
         v8/renderscript \
         v13