Fix closure compiler renaming safety.

[rictic]

JSCompiler_renameProperty can't be exported from a module, it's a global. If it's exported then jscompiler doesn't treat it as special, it's just a normal function.

[dfreedm]

LGTM, but please update changelog

[kwiva]

Currently i'm getting this error when compiling lit element 2.2.1 with the closure compiler 20190929

node_modules/lit-element/lib/updating-element.js:127: 
Originally at:
node_modules/lit-element/src/lib/updating-element.ts:267: ERROR - [JSC_UNDEFINED_VARIABLE] variable JSCompiler_renameProperty is undeclared
            JSCompiler_renameProperty('_classProperties', this))) {
            ^^^^^^^^^^^^^^^^^^^^^^^^^

1 error(s), 0 warning(s)

[rictic]

What flags are you passing to closure compiler? Are you transforming lit-element using clutz?

[kwiva]

This is the list of flags for the closure compiler:

    --compilation_level ADVANCED
    --env BROWSER
    --js node_modules/google-closure-library/closure/goog/array/array.js
...
    --js node_modules/google-closure-library/third_party/closure/goog/mochikit/async/deferred.js
    --js js/demo/boot.js
    --js js/demo/MainModule.js
    --js node_modules/google-closure-library/closure/goog/dom/vendor.js
...
    --js node_modules/google-closure-library/closure/goog/style/style.js
    --js js/demo/ModuleAModule.js
    --js js/demo/bootModuleA.js
    --js node_modules/lit-element/package.json
    --js node_modules/lit-element/lit-element.js
    --js node_modules/lit-element/lib/css-tag.js
    --js node_modules/lit-element/lib/decorators.js
    --js node_modules/lit-element/lib/updating-element.js
    --js node_modules/lit-html/package.json
    --js node_modules/lit-html/lit-html.js
    --js node_modules/lit-html/lib/default-template-processor.js
    --js node_modules/lit-html/lib/directive.js
    --js node_modules/lit-html/lib/dom.js
    --js node_modules/lit-html/lib/modify-template.js
    --js node_modules/lit-html/lib/part.js
    --js node_modules/lit-html/lib/parts.js
    --js node_modules/lit-html/lib/render-options.js
    --js node_modules/lit-html/lib/render.js
    --js node_modules/lit-html/lib/shady-render.js
    --js node_modules/lit-html/lib/template-factory.js
    --js node_modules/lit-html/lib/template-instance.js
    --js node_modules/lit-html/lib/template-processor.js
    --js node_modules/lit-html/lib/template-result.js
    --js node_modules/lit-html/lib/template.js
    --js js/demo/MyElement.js
    --js js/demo/ModuleBModule.js
    --js js/demo/bootModuleB.js
    --language_in ECMASCRIPT_2017
    --language_out ECMASCRIPT_2015
    --strict_mode_input
    --assume_function_wrapper
    --rename_prefix_namespace "_"
    --dependency_mode STRICT
    --entry_point demo.boot
    --entry_point demo.bootModuleA
    --entry_point demo.bootModuleB
    --module_resolution NODE
    --chunk main:101
    --chunk module-a:7:main
    --chunk module-b:24:main
    --chunk_output_path_prefix js/generated/chunks/
    --chunk_wrapper "main:var __DEMO={};(function(_){%output%})(__DEMO);"
    --chunk_wrapper "module-a:(function(_){%output%})(__DEMO);"
    --chunk_wrapper "module-b:(function(_){%output%})(__DEMO);"
    --create_source_map %outname%.map
    --output_chunk_dependencies js/generated/chunks/chunk-dependencies.json
    --output_manifest js/generated/chunks/manifest
    --charset UTF-8
    --define "goog.DEBUG=false"
    --define "goog.json.USE_NATIVE_JSON=true"
    --define "goog.array.ASSUME_NATIVE_FUNCTIONS=true"
    --define "goog.FEATURESET_YEAR=2015"

Both lit-element and lit-html are installed using npm, and the .js files are included. Currently there is no conversion between TS and JS using clutz or tsickle.