[zelos] bump fields to min x position (#3464)

* Bump up all non-text fields in the first row to a min x position.

core/renderers/zelos/info.js

@@ -95,6 +95,20 @@ Blockly.zelos.RenderInfo.prototype.getRenderer = function() {
   return /** @type {!Blockly.zelos.Renderer} */ (this.renderer_);
 };
 
+/**
+ * @override
+ */
+Blockly.zelos.RenderInfo.prototype.measure = function() {
+  // Modifing parent measure method to add `adjustXPosition_`.
+  this.createRows_();
+  this.addElemSpacing_();
+  this.addRowSpacing_();
+  this.adjustXPosition_();
+  this.computeBounds_();
+  this.alignRowElements_();
+  this.finalize_();
+};
+
 /**
  * @override
  */
@@ -202,6 +216,42 @@ Blockly.zelos.RenderInfo.prototype.addAlignmentPadding_ = function(row,
   }
 };
 
+/**
+ * Adjust the x position of fields to bump all non-label fields in the first row
+ * past the notch position.  This must be called before ``computeBounds`` is
+ * called.
+ * @protected
+ */
+Blockly.zelos.RenderInfo.prototype.adjustXPosition_ = function() {
+  if (!this.topRow.hasPreviousConnection) {
+    return;
+  }
+  var minXPos = this.constants_.NOTCH_OFFSET_LEFT +
+      this.constants_.NOTCH_WIDTH;
+  for (var i = 0, row; (row = this.rows[i]); i++) {
+    if (Blockly.blockRendering.Types.isInputRow(row)) {
+      var xCursor = row.xPos;
+      var prevSpacer = null;
+      for (var j = 0, elem; (elem = row.elements[j]); j++) {
+        if (Blockly.blockRendering.Types.isSpacer(elem)) {
+          prevSpacer = elem;
+        }
+        if (prevSpacer && (Blockly.blockRendering.Types.isField(elem) ||
+            Blockly.blockRendering.Types.isInput(elem))) {
+          if (xCursor < minXPos &&
+              !(Blockly.blockRendering.Types.isField(elem) &&
+              elem.field instanceof Blockly.FieldLabel)) {
+            var difference = minXPos - xCursor;
+            prevSpacer.width += difference;
+          }
+        }
+        xCursor += elem.width;
+      }
+      return;
+    }
+  }
+};
+
 /**
  * @override
  */