Make file, lineCount fields optional as per SourceMap v3 spec:
https://docs.google.com/a/google.com/document/d/1U1RGAehQwRypUTovF1KRlpiOFze0b-_2gc6fAH0KY0k/edit

This is to support handling of dart2js source maps, which do not include file, lineCount fields.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=60967049
[New Parser] add fixes and wiring necessary to "pass thru" ES6 class definitions:
CLASS, MEMBER_DEF (and existing GETTER_DEF and SETTER_DEF), and SUPER.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=61000702
Add msExitFullscreen method signature to html5.js.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=61016823
[NEW TYPE INFERENCE]

Add generic classes.
Fix naming class->nominal.
Fix error reporting between GlobalTypeInfo and JSTypeCreatorFromJsdoc.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=61027717