gn2bp: Fix _sanitize_eval_arg and remove workaround codes

Test: ./update_results.sh
Change-Id: Ib43f7f45152c8c4f13db51cd568760db0116a118
diff --git a/tools/gn2bp/gen_android_bp b/tools/gn2bp/gen_android_bp
index 107652c..529eb01 100755
--- a/tools/gn2bp/gen_android_bp
+++ b/tools/gn2bp/gen_android_bp
@@ -774,6 +774,8 @@
     # arg for -e EVAL option should be passed in -e PATCH_HI=int(PATCH)//256 format.
     index = self.target.args.index('-e')
     value = '%s=\'%s\'' % (self.target.args[index + 1], self.target.args[index + 2])
+    # escape '"' in the value
+    value = value.replace('"', r'\"')
     self._set_arg_at(index + 1, value)
     self.target.args.pop(index + 2)
 
@@ -870,12 +872,6 @@
     # Replace {{response_file_contents}} with /dev/stdin
     target.args = ['/dev/stdin' if it == response_file else it for it in target.args]
 
-  # escape " and \$ in target.args.
-  # once all actions are properly implemented, this may not be necessary anymore.
-  # TODO: is this the right place to do this?
-  target.args = [arg.replace('"', r'\"') for arg in target.args]
-  target.args = [arg.replace(r'\$', r'\\$') for arg in target.args]
-
   # put all args on a new line for better diffs.
   NEWLINE = ' " +\n         "'
   arg_string = NEWLINE.join(target.args)