Fix BrowsingDataCounter race condition

chrome/browser/browsing_data/cache_counter.cc

 // Copyright (c) 2015 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/browsing_data/cache_counter.h"
 #include "chrome/browser/profiles/profile.h"
 #include "components/browsing_data/content/conditional_cache_counting_helper.h"
 #include "components/browsing_data/core/pref_names.h"
 #include "content/public/browser/browser_thread.h"
 #include "net/base/net_errors.h"
@@ skipping 14 matching lines @@
 CacheCounter::~CacheCounter() {
 }
 
 const char* CacheCounter::GetPrefName() const {
   return GetTab() == browsing_data::ClearBrowsingDataTab::BASIC
              ? browsing_data::prefs::kDeleteCacheBasic
              : browsing_data::prefs::kDeleteCache;
 }
 
 void CacheCounter::Count() {
+  // Cancel existing requests.
+  weak_ptr_factory_.InvalidateWeakPtrs();
   base::WeakPtr<browsing_data::ConditionalCacheCountingHelper> counter =
       browsing_data::ConditionalCacheCountingHelper::CreateForRange(
           content::BrowserContext::GetDefaultStoragePartition(profile_),
           GetPeriodStart(), base::Time::Max())
           ->CountAndDestroySelfWhenFinished(
               base::Bind(&CacheCounter::OnCacheSizeCalculated,
                          weak_ptr_factory_.GetWeakPtr()));
 }
 
 void CacheCounter::OnCacheSizeCalculated(int64_t result_bytes,
                                          bool is_upper_limit) {
   // A value less than 0 means a net error code.
   if (result_bytes < 0)
     return;
   auto result =
       base::MakeUnique<CacheResult>(this, result_bytes, is_upper_limit);
   ReportResult(std::move(result));
 }