[DevTools] Throttle cache storage list live updates

Creating/deleting a large number of caches at once causes
noticeable slowdowns due to the large number of cache tree
nodes added. Added a time delay between list refreshes to
soften the performance hit.

Also switched to _loadCacheNames since refreshCacheNames
visually removes all caches in the list before re-adding
them.

Bug: 729795
Change-Id: I28edf17671627f90f6d4bb4962cd91028c37f38e
Reviewed-on: https://chromium-review.googlesource.com/625160Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Kristi Park <kristipark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#496568}

third_party/WebKit/Source/devtools/front_end/resources/ApplicationPanelSidebar.js

@@ -770,8 +770,6 @@ Resources.ServiceWorkerCacheTreeElement = class extends Resources.StorageCategor
         SDK.ServiceWorkerCacheModel, SDK.ServiceWorkerCacheModel.Events.CacheAdded, this._cacheAdded, this);
     SDK.targetManager.addModelListener(
         SDK.ServiceWorkerCacheModel, SDK.ServiceWorkerCacheModel.Events.CacheRemoved, this._cacheRemoved, this);
-    this._swCacheModel.addEventListener(
-        SDK.ServiceWorkerCacheModel.Events.CacheStorageListUpdated, this._refreshCaches, this);
     this._swCacheModel.addEventListener(
         SDK.ServiceWorkerCacheModel.Events.CacheStorageContentUpdated, this._cacheContentUpdated, this);
   }

third_party/WebKit/Source/devtools/front_end/sdk/ServiceWorkerCacheModel.js

@@ -22,6 +22,9 @@ SDK.ServiceWorkerCacheModel = class extends SDK.SDKModel {
 
     this._securityOriginManager = target.model(SDK.SecurityOriginManager);
 
+    this._originsUpdated = new Set();
+    this._throttler = new Common.Throttler(2000);
+
     /** @type {boolean} */
     this._enabled = false;
   }
@@ -238,7 +241,15 @@ SDK.ServiceWorkerCacheModel = class extends SDK.SDKModel {
    * @override
    */
   cacheStorageListUpdated(origin) {
-    this.dispatchEventToListeners(SDK.ServiceWorkerCacheModel.Events.CacheStorageListUpdated, {origin: origin});
+    if (origin.endsWith('/'))
+      origin = origin.slice(0, -1);
+    this._originsUpdated.add(origin);
+
+    this._throttler.schedule(() => {
+      var promises = Array.from(this._originsUpdated, origin => this._loadCacheNames(origin));
+      this._originsUpdated.clear();
+      return Promise.all(promises);
+    });
   }
 
   /**
@@ -258,7 +269,6 @@ SDK.SDKModel.register(SDK.ServiceWorkerCacheModel, SDK.Target.Capability.Browser
 SDK.ServiceWorkerCacheModel.Events = {
   CacheAdded: Symbol('CacheAdded'),
   CacheRemoved: Symbol('CacheRemoved'),
-  CacheStorageListUpdated: Symbol('CacheStorageListUpdated'),
   CacheStorageContentUpdated: Symbol('CacheStorageContentUpdated')
 };