Chromium 61 build error.

[Jincheol Jo]

Hi Chrome and Webview team.

I get a android build error when I build old chromium version 61.0.3163.81.

I would like to compile system webview.

 ninja -C out/Release system_webview_apk

[29/20525] ACTION //third_party/We...olchain/android:android_clang_arm)

FAILED: gen/blink/core/CSSOMKeywords.cpp gen/blink/core/CSSOMTypes.cpp 

python ../../third_party/WebKit/Source/build/scripts/core/css/make_cssom_types.py ../../third_party/WebKit/Source/core/css/CSSProperties.json5 --output_dir gen/blink/core

Traceback (most recent call last):

  File "../../third_party/WebKit/Source/build/scripts/core/css/make_cssom_types.py", line 60, in <module>

    json5_generator.Maker(CSSOMTypesWriter).main()

  File "../../third_party/WebKit/Source/build/scripts/core/css/../../json5_generator.py", line 249, in main

    writer = self._writer_class(args.files)

  File "../../third_party/WebKit/Source/build/scripts/core/css/make_cssom_types.py", line 24, in __init__

    super(CSSOMTypesWriter, self).__init__(json5_file_path)

  File "/home/jincheol/workspace/chromium_60/src/third_party/WebKit/Source/build/scripts/core/css/css_properties.py", line 63, in __init__

    self._aliases = [property for property in properties if property['alias_for']]

AssertionError: CSSProperties at least needs both CSSProperties.json5 and             ComputedStyleFieldAliases.json5 to function

[38/20525] ACTION //third_party/an...olchain/android:android_clang_arm)

ninja: build stopped: subcommand failed.

```

What should I do for that issue?

Thanks for any response.

// jincheol