Log the time interval between adjacent JumpList update notifications

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 "base/base_paths.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
@@ skipping 291 matching lines @@
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
   if (icon_urls_.empty())
     PostRunUpdate();
 }
 
 void JumpList::InitializeTimerForUpdate() {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
   if (timer_.IsRunning()) {
+    // TODO(chengx): Remove the UMA histogram below after fixing crbug/733034.
+    UMA_HISTOGRAM_COUNTS_10000(
+        "WinJumplist.NotificationTimeInterval",
+        (timer_.desired_run_time() - base::TimeTicks::Now()).InMilliseconds());
     timer_.Reset();
   } else {
     // base::Unretained is safe since |this| is guaranteed to outlive timer_.
     timer_.Start(FROM_HERE, kDelayForJumplistUpdate,
                  base::Bind(&JumpList::OnDelayTimer, base::Unretained(this)));
   }
 }
 
 void JumpList::OnDelayTimer() {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
@@ skipping 541 matching lines @@
                                const URLIconCache& icons_cache) {
   // Put all cached icon file paths into a set.
   base::flat_set<base::FilePath> cached_files;
   cached_files.reserve(icons_cache.size());
 
   for (const auto& url_path_pair : icons_cache)
     cached_files.insert(url_path_pair.second);
 
   DeleteNonCachedFiles(icon_dir, cached_files);
 }