chore(scripts): fail on pipe failures

Closes #922
Closes #1172
Closes #1289
Closes #1291
doc(WebPlatform): improve the inline doc
refactor(WebPlatform): remove an unused property
chore(style): cleanup to match g3v1x
chore(view_factory): register cache as ViewCache
fix(web_platform): include selector in viewFactoryCache key
chore(introspection): delete introspection_js.dart

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