Separate out android specifics from client_ext.

Change-Id: Ia3009134c54764fe42700205e56ffe8de4d8a536
Bug: 160399441
Bug: 160400319
Bug: 141241849
diff --git a/Android.bp b/Android.bp
index b5cf2a1..0c01f57 100644
--- a/Android.bp
+++ b/Android.bp
@@ -6246,6 +6246,7 @@
   name: "perfetto_src_profiling_memory_client_ext",
   srcs: [
     "src/profiling/memory/client_ext.cc",
+    "src/profiling/memory/client_ext_android.cc",
   ],
 }