Clean up code in FieldTextInput (#1284)
Clean up code in FieldTextInput (#1284)

* Clean up code in FieldTextInput

* Explicit annotations

* Remove extra newline

nickmain/blockly,google/blockly,google/blockly,trinketapp/blockly,mark-friedman/blockly,twodee/blockly,nickmain/blockly,google/blockly,rachel-fenichel/blockly,jstnhuang/blockly,mark-friedman/blockly,google/blockly,twodee/blockly,joshlory/blockly,rachel-fenichel/blockly,jstnhuang/blockly,rachel-fenichel/blockly,trodi/blockly,google/blockly,nickmain/blockly,trodi/blockly,mark-friedman/blockly,mark-friedman/blockly,groklearning/blockly,twodee/blockly,nickmain/blockly,picklesrus/blockly,picklesrus/blockly,joshlory/blockly,google/blockly,twodee/blockly,picklesrus/blockly,nickmain/blockly,nickmain/blockly,trodi/blockly,mark-friedman/blockly,joshlory/blockly,twodee/blockly,trinketapp/blockly,rachel-fenichel/blockly,jstnhuang/blockly,twodee/blockly,groklearning/blockly,jstnhuang/blockly,google/blockly,rachel-fenichel/blockly,groklearning/blockly,trinketapp/blockly,trinketapp/blockly,rachel-fenichel/blockly,trodi/blockly,mark-friedman/blockly,groklearning/blockly,rachel-fenichel/blockly