Bug 1783261 - Measure the result text length in the text recognition modal; r=nordzilla

Differential Revision: https://phabricator.services.mozilla.com/D154895

browser/components/textrecognition/tests/browser/browser_textrecognition.js

@@ -97,10 +97,15 @@ add_task(async function() {
     const close = contentDocument.querySelector("#text-recognition-close");
     close.click();
 
+    const expectedResultText = "Mozilla\nFirefox\n";
+    is(getTextFromClipboard(), expectedResultText, "The copied text matches.");
+
     is(
-      getTextFromClipboard(),
-      "Mozilla\nFirefox\n",
-      "The copied text matches."
+      Services.telemetry
+        .getHistogramById("TEXT_RECOGNITION_TEXT_LENGTH")
+        .snapshot().sum,
+      expectedResultText.length,
+      "The length of the text was recorded."
     );
 
     info("Waiting for the dialog frame to close.");

browser/components/textrecognition/tests/browser/head.js

@@ -51,4 +51,5 @@ function clearTelemetry() {
   Services.telemetry
     .getHistogramById("TEXT_RECOGNITION_INTERACTION_TIMING")
     .clear();
+  Services.telemetry.getHistogramById("TEXT_RECOGNITION_TEXT_LENGTH").clear();
 }

browser/components/textrecognition/textrecognition.mjs

@@ -112,6 +112,17 @@ class TextRecognitionModal {
     window.addEventListener("unload", finish);
   }
 
+  /**
+   * After the results are shown, measure how long a user interacts with the modal.
+   * @param {number} length
+   */
+  static recordTextLengthTelemetry(length) {
+    const histogram = Services.telemetry.getHistogramById(
+      "TEXT_RECOGNITION_TEXT_LENGTH"
+    );
+    histogram.add(length);
+  }
+
   setupCloseHandler() {
     document
       .querySelector("#text-recognition-close")
@@ -215,6 +226,7 @@ class TextRecognitionModal {
     this.textEl.style.display = "block";
 
     TextRecognitionModal.copy(text);
+    TextRecognitionModal.recordTextLengthTelemetry(text.length);
   }
 }
 

toolkit/components/telemetry/Histograms.json

@@ -17101,6 +17101,18 @@
     "bug_numbers": [1783261],
     "description": "The milliseconds of time that a user viewed the text results."
   },
+  "TEXT_RECOGNITION_TEXT_LENGTH": {
+    "record_in_processes": ["main"],
+    "products": ["firefox"],
+    "releaseChannelCollection": "opt-out",
+    "alert_emails": ["gtatum@mozilla.com", "nordzilla@mozilla.com"],
+    "expires_in_version": "109",
+    "kind": "exponential",
+    "high": 50000,
+    "n_buckets": 20,
+    "bug_numbers": [1783261],
+    "description": "Measures the length of the text that was recognized, in code units."
+  },
   "DOWNLOADS_USER_ACTION_ON_BLOCKED_DOWNLOAD": {
     "record_in_processes": ["main"],
     "products": ["firefox"],