gn2bp: add support for cpp files

libc++ sources end in .cpp.

Test: //components/cronet/android:cronet
Change-Id: I7f6dfa8a80bcd13cfc52921e20e404cb029c2bd9
diff --git a/tools/gn2bp/gen_android_bp b/tools/gn2bp/gen_android_bp
index 2caf805..c53c8ed 100755
--- a/tools/gn2bp/gen_android_bp
+++ b/tools/gn2bp/gen_android_bp
@@ -490,7 +490,7 @@
 
 def is_supported_source_file(name):
   """Returns True if |name| can appear in a 'srcs' list."""
-  return os.path.splitext(name)[1] in ['.c', '.cc', '.java', '.proto']
+  return os.path.splitext(name)[1] in ['.c', '.cc', '.cpp', '.java', '.proto']
 
 
 def create_proto_modules(blueprint, gn, target):