Merge 232142 "Revert 230138 "Delay wallpaper load by 2 * average..."

chrome/browser/resources/chromeos/login/user_pod_row.js

Index: chrome/browser/resources/chromeos/login/user_pod_row.js
===================================================================
--- chrome/browser/resources/chromeos/login/user_pod_row.js	(revision 232150)
+++ chrome/browser/resources/chromeos/login/user_pod_row.js	(working copy)
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-<include src="wallpaper_loader.js"></include>
-
 /**
  * @fileoverview User pod row implementation.
  */
@@ -24,6 +22,20 @@
   var PRESELECT_FIRST_POD = true;
 
   /**
+   * Wallpaper load delay in milliseconds.
+   * @type {number}
+   * @const
+   */
+  var WALLPAPER_LOAD_DELAY_MS = 500;
+
+  /**
+   * Wallpaper load delay in milliseconds. TODO(nkostylev): Tune this constant.
+   * @type {number}
+   * @const
+   */
+  var WALLPAPER_BOOT_LOAD_DELAY_MS = 100;
+
+  /**
    * Maximum time for which the pod row remains hidden until all user images
    * have been loaded.
    * @type {number}
@@ -947,9 +959,17 @@
     // Whether this user pod row is shown for the first time.
     firstShown_: true,
 
+    // Whether the initial wallpaper load after boot has been requested. Used
+    // only if |Oobe.getInstance().shouldLoadWallpaperOnBoot()| is true.
+    bootWallpaperLoaded_: false,
+
     // True if inside focusPod().
     insideFocusPod_: false,
 
+    // True if user pod has been activated with keyboard.
+    // In case of activation with keyboard we delay wallpaper change.
+    keyboardActivated_: false,
+
     // Focused pod.
     focusedPod_: undefined,
 
@@ -959,8 +979,9 @@
     // Pod that was most recently focused, if any.
     lastFocusedPod_: undefined,
 
-    // Note: created only in decorate() !
-    wallpaperLoader_: undefined,
+    // When moving through users quickly at login screen, set a timeout to
+    // prevent loading intermediate wallpapers.
+    loadWallpaperTimeout_: null,
 
     // Pods whose initial images haven't been loaded yet.
     podsWithPendingImages_: [],
@@ -977,7 +998,6 @@
         mousemove: [this.handleMouseMove_.bind(this), false],
         keydown: [this.handleKeyDown.bind(this), false]
       };
-      this.wallpaperLoader_ = new login.WallpaperLoader();
     },
 
     /**
@@ -1222,7 +1242,7 @@
       }
       this.insideFocusPod_ = true;
 
-      this.wallpaperLoader_.reset();
+      clearTimeout(this.loadWallpaperTimeout_);
       for (var i = 0, pod; pod = this.pods[i]; ++i) {
         if (!this.isSinglePod) {
           pod.isActionBoxMenuActive = false;
@@ -1246,8 +1266,15 @@
         podToFocus.classList.add('focused');
         podToFocus.reset(true);  // Reset and give focus.
         chrome.send('focusPod', [podToFocus.user.emailAddress]);
-
-        this.wallpaperLoader_.scheduleLoad(podToFocus.user.emailAddress);
+        if (hadFocus && this.keyboardActivated_) {
+          // Delay wallpaper loading to let user tab through pods without lag.
+          this.loadWallpaperTimeout_ = window.setTimeout(
+              this.loadWallpaper_.bind(this), WALLPAPER_LOAD_DELAY_MS);
+        } else if (!this.firstShown_) {
+          // Load wallpaper immediately if there no pod was focused
+          // previously, and it is not a boot into user pod list case.
+          this.loadWallpaper_();
+        }
         this.firstShown_ = false;
         this.lastFocusedPod_ = podToFocus;
       }
@@ -1256,19 +1283,20 @@
     },
 
     /**
-     * Resets wallpaper to the last active user's wallpaper, if any.
+     * Loads wallpaper for the active user pod, if any.
+     * @private
      */
-    loadLastWallpaper: function() {
-      if (this.lastFocusedPod_)
-        this.wallpaperLoader_.scheduleLoad(this.lastFocusedPod_.user.username);
+    loadWallpaper_: function() {
+      if (this.focusedPod_)
+        chrome.send('loadWallpaper', [this.focusedPod_.user.username]);
     },
 
     /**
-     * Handles 'onWallpaperLoaded' event. Recalculates statistics and
-     * [re]schedules next wallpaper load.
+     * Resets wallpaper to the last active user's wallpaper, if any.
      */
-    onWallpaperLoaded: function(email) {
-      this.wallpaperLoader_.onWallpaperLoaded(email);
+    loadLastWallpaper: function() {
+      if (this.lastFocusedPod_)
+        chrome.send('loadWallpaper', [this.lastFocusedPod_.user.username]);
     },
 
     /**
@@ -1532,7 +1560,13 @@
             focusedPod.reset(true);
             // Notify screen that it is ready.
             screen.onShow();
-            self.wallpaperLoader_.scheduleLoad(focusedPod.user.username);
+            // Boot transition: load wallpaper.
+            if (!self.bootWallpaperLoaded_ &&
+                Oobe.getInstance().shouldLoadWallpaperOnBoot()) {
+              self.loadWallpaperTimeout_ = window.setTimeout(
+                  self.loadWallpaper_.bind(self), WALLPAPER_BOOT_LOAD_DELAY_MS);
+              self.bootWallpaperLoaded_ = true;
+            }
           }
         });
         // Guard timer for 1 second -- it would conver all possible animations.