Fixed Procedure Argument Escaping (#2626)
Fixed Procedure Argument Escaping (#2626)

* Refactored procedure decompose to build XML node by node. Fixed argument name escaping.

* Fixed review comments.

joshlory/blockly,picklesrus/blockly,mark-friedman/blockly,nickmain/blockly,picklesrus/blockly,joshlory/blockly,rachel-fenichel/blockly,mark-friedman/blockly,rachel-fenichel/blockly,google/blockly,google/blockly,mark-friedman/blockly,rachel-fenichel/blockly,rachel-fenichel/blockly,rachel-fenichel/blockly,nickmain/blockly,google/blockly,rachel-fenichel/blockly,nickmain/blockly,google/blockly,nickmain/blockly,mark-friedman/blockly,picklesrus/blockly,google/blockly,google/blockly,rachel-fenichel/blockly,google/blockly,nickmain/blockly,mark-friedman/blockly,nickmain/blockly,mark-friedman/blockly,joshlory/blockly