Filter out redundant jumplist updates.

chrome/browser/jumplist_win.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/jumplist_win.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/files/file_util.h"
 #include "base/path_service.h"
 #include "base/prefs/pref_change_registrar.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread.h"
+#include "base/trace_event/trace_event.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/favicon/favicon_service_factory.h"
 #include "chrome/browser/history/top_sites_factory.h"
 #include "chrome/browser/metrics/jumplist_metrics_win.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sessions/tab_restore_service.h"
 #include "chrome/browser/sessions/tab_restore_service_factory.h"
 #include "chrome/browser/shell_integration.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_switches.h"
@@ skipping 13 matching lines @@
 #include "ui/gfx/codec/png_codec.h"
 #include "ui/gfx/favicon_size.h"
 #include "ui/gfx/icon_util.h"
 #include "ui/gfx/image/image_family.h"
 #include "url/gurl.h"
 
 using content::BrowserThread;
 
 namespace {
 
+// Delay jumplist updates to allow collapsing of redundant update requests.
+const int kDelayForJumplistUpdateInMS = 3500;
+
 // Append the common switches to each shell link.
 void AppendCommonSwitches(ShellLinkItem* shell_link) {
   const char* kSwitchNames[] = { switches::kUserDataDir };
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
   shell_link->GetCommandLine()->CopySwitchesFrom(command_line,
                                                  kSwitchNames,
                                                  arraysize(kSwitchNames));
 }
 
@@ skipping 374 matching lines @@
     base::AutoLock auto_lock(list_lock_);
     waiting_for_icons = !icon_urls_.empty();
   }
   if (!waiting_for_icons)
     PostRunUpdate();
   // If |icon_urls_| isn't empty then OnFaviconDataAvailable will eventually
   // call PostRunUpdate().
 }
 
 void JumpList::PostRunUpdate() {
+  TRACE_EVENT0("browser", "JumpList::PostRunUpdate");
+  // Initialize the one-shot timer to update the jumplists in a while.
+  // If there is already a request queued then cancel it and post the new
+  // request. This ensures that JumpListUpdates won't happen until there has
+  // been a brief quiet period, thus avoiding update storms.
+  if (timer_.IsRunning()) {
+    timer_.Reset();
+  } else {
+    timer_.Start(FROM_HERE,
+                 base::TimeDelta::FromMilliseconds(kDelayForJumplistUpdateInMS),
+                 this,
+                 &JumpList::DeferredRunUpdate);
+  }
+}
+
+void JumpList::DeferredRunUpdate() {
+  TRACE_EVENT0("browser", "JumpList::DeferredRunUpdate");
   // Check if incognito windows (or normal windows) are disabled by policy.
   IncognitoModePrefs::Availability incognito_availability =
       profile_ ? IncognitoModePrefs::GetAvailability(profile_->GetPrefs())
                : IncognitoModePrefs::ENABLED;
 
   BrowserThread::PostTask(
       BrowserThread::FILE, FROM_HERE,
       base::Bind(&JumpList::RunUpdateOnFileThread,
                  this,
                  incognito_availability));
@@ skipping 52 matching lines @@
 
 void JumpList::TopSitesLoaded(history::TopSites* top_sites) {
 }
 
 void JumpList::TopSitesChanged(history::TopSites* top_sites) {
   top_sites->GetMostVisitedURLs(
       base::Bind(&JumpList::OnMostVisitedURLsAvailable,
                  weak_ptr_factory_.GetWeakPtr()),
       false);
 }