Use flex to compute measure font metrics (#3714)
Use flex to compute measure font metrics (#3714)

* Use flexbox to compute font dimensions instead of inline-block

mark-friedman/blockly,rachel-fenichel/blockly,mark-friedman/blockly,rachel-fenichel/blockly,rachel-fenichel/blockly,google/blockly,google/blockly,mark-friedman/blockly,google/blockly,mark-friedman/blockly,google/blockly,google/blockly,rachel-fenichel/blockly,rachel-fenichel/blockly,mark-friedman/blockly,mark-friedman/blockly,google/blockly,rachel-fenichel/blockly,google/blockly,rachel-fenichel/blockly