code: function Document(file, initialTimestamp, rawText) {
          this.file = file;
          this.editable = !file.readOnly;
          this._updateLanguage();
          this.refreshText(rawText, initialTimestamp, true);
          // List of full editors which are initialized as master editors for this doc.
          this._associatedFullEditors = [];
      }
docs: Model for the contents of a single file and its current modification state.
  See DocumentManager documentation for important usage notes.
  
  Document dispatches these events:
  
  __change__ -- When the text of the editor changes (including due to undo/redo).
  
  Passes ({Document}, {ChangeList}), where ChangeList is an array
  of change record objects. Each change record looks like:
  
  { from: start of change, expressed as {line: <line number>, ch: <character offset>},
  to: end of change, expressed as {line: <line number>, ch: <chracter offset>},
  text: array of lines of text to replace existing text }
  
  The line and ch offsets are both 0-based.
  
  The ch offset in "from" is inclusive, but the ch offset in "to" is exclusive. For example,
  an insertion of new content (without replacing existing content) is expressed by a range
  where from and to are the same.
  
  If "from" and "to" are undefined, then this is a replacement of the entire text content.
  
  IMPORTANT: If you listen for the "change" event, you MUST also addRef() the document
  (and releaseRef() it whenever you stop listening). You should also listen to the "deleted"
  event.
  
  __deleted__ -- When the file for this document has been deleted. All views onto the document should
  be closed. The document will no longer be editable or dispatch "change" events.
  
  __languageChanged__ -- When the value of getLanguage() has changed. 2nd argument is the old value,
  3rd argument is the new value.
  
  @constructor
  @param {!File} file  Need not lie within the project.
  @param {!Date} initialTimestamp  File's timestamp when we read it off disk.
  @param {!string} rawText  Text content of the file.