gn2bp: Add _sanitize_args to JavaCppStringSanitizer

Test: m cronet_aml_base_java_switches_srcjar
Change-Id: I02c1d68aa824352cecb88c105a1dda990a5d17de
diff --git a/tools/gn2bp/gen_android_bp b/tools/gn2bp/gen_android_bp
index e04172e..45edbb0 100755
--- a/tools/gn2bp/gen_android_bp
+++ b/tools/gn2bp/gen_android_bp
@@ -908,7 +908,10 @@
     super()._sanitize_args()
 
 class JavaCppStringSanitizer(BaseActionSanitizer):
-  pass
+  def _sanitize_args(self):
+    self._update_all_args(self._sanitize_filepath_with_location_tag)
+    self._set_value_arg('--srcjar', '$(out)')
+    super()._sanitize_args()
 
 def get_action_sanitizer(target, type):
   if target.script == "//build/write_buildflag_header.py":