Bug 1406097 - Use the cached attribution code in the environment. r=mhowell

This adds a new sync function to AttributionCode.jsm that returns the cached
attribution data. The cached data is then used to populate the environment
instead of relying on the async function.

MozReview-Commit-ID: F0se7kXspo2

--HG--
extra : rebase_source : 0a2631651e3da6edde9592eabd354b070ffa6ae8

browser/modules/AttributionCode.jsm

@@ -90,6 +90,16 @@ var AttributionCode = {
     })();
   },
 
+  /**
+   * Return the cached attribution data synchronously without hitting
+   * the disk.
+   * @returns A dictionary with the attribution data if it's available,
+   *          null otherwise.
+   */
+  getCachedAttributionData() {
+    return gCachedAttrData;
+  },
+
   /**
    * Deletes the attribution data file.
    * Returns a promise that resolves when the file is deleted,

toolkit/components/telemetry/TelemetryEnvironment.jsm

@@ -867,7 +867,7 @@ function EnvironmentCache() {
   this._currentEnvironment.profile = {};
   p.push(this._updateProfile());
   if (AppConstants.MOZ_BUILD_APP == "browser") {
-    p.push(this._updateAttribution());
+    p.push(this._loadAttributionAsync());
   }
 
   for (const [id, {branch, options}] of gActiveExperimentStartupBuffer.entries()) {
@@ -1363,13 +1363,7 @@ EnvironmentCache.prototype = {
       updateChannel = UpdateUtils.getUpdateChannel(false);
     } catch (e) {}
 
-    // Make sure to retain the attribution code across environment changes.
-    const attributionCode =
-      (this._currentEnvironment.settings &&
-       this._currentEnvironment.settings.attribution) || {};
-
     this._currentEnvironment.settings = {
-      attribution: attributionCode,
       blocklistEnabled: Services.prefs.getBoolPref(PREF_BLOCKLIST_ENABLED, true),
       e10sEnabled: Services.appinfo.browserTabsRemoteAutostart,
       e10sMultiProcesses: Services.appinfo.maxWebProcessCount,
@@ -1388,6 +1382,7 @@ EnvironmentCache.prototype = {
     this._currentEnvironment.settings.addonCompatibilityCheckEnabled =
       AddonManager.checkCompatibility;
 
+    this._updateAttribution();
     this._updateDefaultBrowser();
     this._updateSearchEngine();
   },
@@ -1425,18 +1420,42 @@ EnvironmentCache.prototype = {
   },
 
   /**
-   * Update the cached attribution data object.
+   * Load the attribution data object and updates the environment.
    * @returns Promise<> resolved when the I/O is complete.
    */
-  async _updateAttribution() {
-    let data = await AttributionCode.getAttrDataAsync();
-    if (Object.keys(data).length > 0) {
-      this._currentEnvironment.settings.attribution = {};
-      for (let key in data) {
-        this._currentEnvironment.settings.attribution[key] =
-          limitStringToLength(data[key], MAX_ATTRIBUTION_STRING_LENGTH);
-      }
+  async _loadAttributionAsync() {
+    try {
+      await AttributionCode.getAttrDataAsync();
+    } catch (e) {
+      // The AttributionCode.jsm module might not be always available
+      // (e.g. tests). Gracefully handle this.
+      return;
     }
+    this._updateAttribution();
+  },
+
+  /**
+   * Update the environment with the cached attribution data.
+   */
+  _updateAttribution() {
+    let data = null;
+    try {
+      data = AttributionCode.getCachedAttributionData();
+    } catch (e) {
+      // The AttributionCode.jsm module might not be always available
+      // (e.g. tests). Gracefully handle this.
+    }
+
+    if (!data || !Object.keys(data).length) {
+      return;
+    }
+
+    let attributionData = {};
+    for (let key in data) {
+      attributionData[key] =
+        limitStringToLength(data[key], MAX_ATTRIBUTION_STRING_LENGTH);
+    }
+    this._currentEnvironment.settings.attribution = attributionData;
   },
 
   /**