added gcm repo

Change-Id: I632911500290714b77127aaf9d12934286ed7a8b
diff --git a/default_unrestricted.xml b/default_unrestricted.xml
index 41dbbb6..cb7cc37 100644
--- a/default_unrestricted.xml
+++ b/default_unrestricted.xml
@@ -43,6 +43,7 @@
   <project name="vendor/google/dvbcapture"/>
   <project name="vendor/google/freetypejni"/>
   <project name="vendor/google/frob"/>
+  <project name="vendor/google/gcm"/>
   <project name="vendor/google/gips"/>
   <project name="vendor/google/gl_dart"/>
   <project name="vendor/google/glfw_dart"/>