gn2bp: Fix otuput file path for jni_registration_generator.py

Test: ./update_results.sh
Change-Id: I7a0246d09dd18413ef9bdffe8910f7b1f453d9af
diff --git a/tools/gn2bp/gen_android_bp b/tools/gn2bp/gen_android_bp
index bbd3cda..9aa2f2a 100755
--- a/tools/gn2bp/gen_android_bp
+++ b/tools/gn2bp/gen_android_bp
@@ -812,6 +812,10 @@
     # TODO: find a better way to do this.
     target.deps.clear()
 
+    for i, val in enumerate(target.args):
+      if val in ['--depfile', '--srcjar-path', '--header-path']:
+        target.args[i + 1] = re.sub('^gen', '$(genDir)', target.args[i + 1])
+
   elif target.script == '//build/android/gyp/write_build_config.py':
     for i, val in enumerate(target.args):
       if val == '--depfile':