Cancel the JumpList update if top 5 most visited URLs are unchanged

chrome/browser/win/jumplist.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/win/jumplist.h"
 
+#include <algorithm>
+#include <iterator>
+
 #include "base/base_paths.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/containers/flat_set.h"
 #include "base/files/file_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/path_service.h"
 #include "base/sequenced_task_runner.h"
 #include "base/single_thread_task_runner.h"
@@ skipping 169 matching lines @@
 // Returns the full path of the JumpListIcons[|suffix|] directory in
 // |profile_dir|.
 base::FilePath GenerateJumplistIconDirName(
     const base::FilePath& profile_dir,
     const base::FilePath::StringPieceType& suffix) {
   base::FilePath::StringType dir_name(chrome::kJumpListIconDirname);
   suffix.AppendToString(&dir_name);
   return profile_dir.Append(dir_name);
 }
 
+// Checks if the urls stored in |items| have new ones coming from |urls|.
+bool HasNewMostVisitedItems(const ShellLinkItemList& items,
+                            const history::MostVisitedURLList& urls) {
+  // If the number of the top sites going to be displayed is larger than the
+  // current one, or if the available urls from TopSites are fewer than the ones
+  // currenlty in display, we consider there are new most visited items.
+  // Otherwise, check if the current urls stored in |items| are different from
+  // |urls| to determine if there are new items.
+
+  size_t topsites_count_updated = std::min(urls.size(), kMostVisitedItems);
+  if (topsites_count_updated > items.size() || urls.size() < items.size())
+    return true;
+
+  return std::equal(std::begin(items), std::end(items), std::begin(urls),

[grt (UTC plus 2), 2017/05/29 07:14:44]

shouldn't this return false if the ranges are equal since that indicates that
the top N urls haven't changed?

[chengx, 2017/05/30 02:56:44]

You're right. I've fixed this in the new patch set.

+                    [](const auto& item_ptr, const auto& most_visited_url) {
+                      return item_ptr->url() == most_visited_url.url.spec();
+                    });
+}
+
 }  // namespace
 
 JumpList::JumpListData::JumpListData() {}
 
 JumpList::JumpListData::~JumpListData() {}
 
 JumpList::JumpList(Profile* profile)
     : RefcountedKeyedService(content::BrowserThread::GetTaskRunnerForThread(
           content::BrowserThread::UI)),
       profile_(profile),
@@ skipping 79 matching lines @@
   Terminate();
 }
 
 void JumpList::OnMostVisitedURLsAvailable(
     const history::MostVisitedURLList& urls) {
   DCHECK(CalledOnValidThread());
 
   {
     JumpListData* data = &jumplist_data_->data;
     base::AutoLock auto_lock(data->list_lock_);
+
+    // There is no need to update the JumpList if the top most visited sites in
+    // display have not changed.
+    if (!HasNewMostVisitedItems(data->most_visited_pages_, urls))
+      return;
+
     data->most_visited_pages_.clear();
 
     for (size_t i = 0; i < urls.size() && i < kMostVisitedItems; i++) {
       const history::MostVisitedURL& url = urls[i];
       scoped_refptr<ShellLinkItem> link = CreateShellLink();
       std::string url_string = url.url.spec();
       base::string16 url_string_wide = base::UTF8ToUTF16(url_string);
       link->GetCommandLine()->AppendArgNative(url_string_wide);
       link->GetCommandLine()->AppendSwitchASCII(
           switches::kWinJumplistAction, jumplist::kMostVisitedCategory);
@@ skipping 551 matching lines @@
           app_id, profile_dir, local_most_visited_pages,
           local_recently_closed_pages, most_visited_pages_have_updates,
           recently_closed_pages_have_updates, incognito_availability)) {
     base::AutoLock auto_lock(data->list_lock_);
     if (most_visited_pages_have_updates)
       data->most_visited_pages_have_updates_ = true;
     if (recently_closed_pages_have_updates)
       data->recently_closed_pages_have_updates_ = true;
   }
 }