Add visual reporting of top-level reporter execution

src/engine/runtime.js

@@ -69,6 +69,12 @@ Runtime.BLOCK_GLOW_ON = 'BLOCK_GLOW_ON';
  */
 Runtime.BLOCK_GLOW_OFF = 'BLOCK_GLOW_OFF';
 
+/**
+ * Event name for visual value report.
+ * @const {string}
+ */
+Runtime.VISUAL_REPORT = 'VISUAL_REPORT';
+
 /**
  * Inherit from EventEmitter
  */
@@ -218,6 +224,15 @@ Runtime.prototype.glowBlock = function (blockId, isGlowing) {
     }
 };
 
+/**
+ * Emit value for reporter to show in the blocks.
+ * @param {string} blockId ID for the block.
+ * @param {string} value Value to show associated with the block.
+ */
+Runtime.prototype.visualReport = function (blockId, value) {
+    this.emit(Runtime.VISUAL_REPORT, blockId, String(value));
+};
+
 /**
  * Return the Target for a particular thread.
  * @param {!Thread} thread Thread to determine target for.