Bug 721019 - [Page Thumbnails] Add telemetry probes; r=dietrich

browser/components/thumbnails/PageThumbs.jsm

@@ -77,6 +77,7 @@ let PageThumbs = {
    * @return The newly created canvas containing the image data.
    */
   capture: function PageThumbs_capture(aWindow) {
+    let telemetryCaptureTime = new Date();
     let [sw, sh, scale] = this._determineCropSize(aWindow);
 
     let canvas = this._createCanvas();
@@ -93,6 +94,9 @@ let PageThumbs = {
       // We couldn't draw to the canvas for some reason.
     }
 
+    Services.telemetry.getHistogramById("FX_THUMBNAILS_CAPTURE_TIME_MS")
+      .add(new Date() - telemetryCaptureTime);
+
     return canvas;
   },
 
@@ -105,13 +109,20 @@ let PageThumbs = {
    *                  stored (optional).
    */
   store: function PageThumbs_store(aKey, aCanvas, aCallback) {
-    let self = this;
+    let telemetryStoreTime = new Date();
 
     function finish(aSuccessful) {
+      if (aSuccessful) {
+        Services.telemetry.getHistogramById("FX_THUMBNAILS_STORE_TIME_MS")
+          .add(new Date() - telemetryStoreTime);
+      }
+
       if (aCallback)
         aCallback(aSuccessful);
     }
 
+    let self = this;
+
     // Get a writeable cache entry.
     PageThumbsCache.getWriteEntry(aKey, function (aEntry) {
       if (!aEntry) {

browser/components/thumbnails/PageThumbsProtocol.js

@@ -129,12 +129,18 @@ Channel.prototype = {
 
     // Try to read the data from the thumbnail cache.
     this._readCache(function (aData) {
+      let telemetryThumbnailFound = true;
+
       // Update response if there's no data.
       if (!aData) {
         this._responseStatus = 404;
         this._responseText = "Not Found";
+        telemetryThumbnailFound = false;
       }
 
+      Services.telemetry.getHistogramById("FX_THUMBNAILS_HIT_OR_MISS")
+        .add(telemetryThumbnailFound);
+
       this._startRequest();
 
       if (!this.canceled) {

toolkit/components/telemetry/TelemetryHistograms.h

@@ -313,6 +313,13 @@ HISTOGRAM(FX_TAB_ANIM_OPEN_MS, 1, 3000, 10, EXPONENTIAL, "Firefox: Time taken by
 HISTOGRAM(FX_TAB_ANIM_CLOSE_MS, 1, 3000, 10, EXPONENTIAL, "Firefox: Time taken by the tab closing animation in milliseconds")
 HISTOGRAM_BOOLEAN(FX_CONTEXT_SEARCH_AND_TAB_SELECT, "Firefox: Background tab was selected within 5 seconds of searching from the context menu")
 HISTOGRAM(FX_IDENTITY_POPUP_OPEN_MS, 1, 1000, 10, EXPONENTIAL, "Firefox: Time taken by the identity popup to open in milliseconds")
+
+/**
+ * Thumbnail Service telemetry.
+ */
+HISTOGRAM(FX_THUMBNAILS_CAPTURE_TIME_MS, 1, 500, 15, EXPONENTIAL, "THUMBNAILS: Time (ms) it takes to capture a thumbnail")
+HISTOGRAM(FX_THUMBNAILS_STORE_TIME_MS, 1, 500, 15, EXPONENTIAL, "THUMBNAILS: Time (ms) it takes to store a thumbnail in the cache")
+HISTOGRAM(FX_THUMBNAILS_HIT_OR_MISS, 0, 1, 2, BOOLEAN, "THUMBNAILS: Thumbnail found")
 // #endif
 
 HISTOGRAM_BOOLEAN(INNERWINDOWS_WITH_MUTATION_LISTENERS, "Deleted or to-be-reused innerwindow which has had mutation event listeners.")