Removing AccessLog class. This is a partial revert of yzshen's r74872.

net/url_request/url_request_throttler_manager.cc

 // Copyright (c) 2010 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 "net/url_request/url_request_throttler_manager.h"
 
 #include <list>
 
 #include "base/logging.h"
 #include "base/string_util.h"
-#include "base/synchronization/lock.h"
-#include "base/threading/platform_thread.h"
-
-namespace {
-
-// AccessLog records threads that have accessed the URLRequestThrottlerManager
-// singleton object.
-// TODO(yzshen): It is used for diagnostic purpose and should be removed once we
-// figure out crbug.com/71721
-class AccessLog {
- public:
-  static const size_t kAccessLogSize = 4;
-
-  AccessLog() {
-    for (size_t i = 0; i < kAccessLogSize; ++i) {
-      thread_ids_[i] = base::kInvalidThreadId;
-      urls_[i][0] = '\0';
-    }
-  }
-
-  AccessLog(const AccessLog& log) {
-    base::AutoLock auto_lock(log.lock_);
-    for (size_t i = 0; i < kAccessLogSize; ++i) {
-      thread_ids_[i] = log.thread_ids_[i];
-      base::strlcpy(urls_[i], log.urls_[i], kUrlBufferSize);
-    }
-  }
-
-  void Add(base::PlatformThreadId id, const GURL& url) {
-    base::AutoLock auto_lock(lock_);
-    for (size_t i = 0; i < kAccessLogSize; ++i) {
-      if (thread_ids_[i] == id) {
-        return;
-      } else if (thread_ids_[i] == base::kInvalidThreadId) {
-        DCHECK(i == 0);
-        thread_ids_[i] = id;
-        base::strlcpy(urls_[i], url.spec().c_str(), kUrlBufferSize);
-        return;
-      }
-    }
-  }
-
- private:
-  static const size_t kUrlBufferSize = 128;
-
-  mutable base::Lock lock_;
-  base::PlatformThreadId thread_ids_[kAccessLogSize];
-  // Records the URL argument of the first RegisterRequestUrl() call on each
-  // thread.
-  char urls_[kAccessLogSize][kUrlBufferSize];
-};
-
-AccessLog access_log;
-
-}  // namespace
 
 namespace net {
 
 const unsigned int URLRequestThrottlerManager::kMaximumNumberOfEntries = 1500;
 const unsigned int URLRequestThrottlerManager::kRequestsBetweenCollecting = 200;
 
 URLRequestThrottlerManager* URLRequestThrottlerManager::GetInstance() {
   return Singleton<URLRequestThrottlerManager>::get();
 }
 
 scoped_refptr<URLRequestThrottlerEntryInterface>
     URLRequestThrottlerManager::RegisterRequestUrl(const GURL &url) {
-  if (record_access_log_)
-    access_log.Add(base::PlatformThread::CurrentId(), url);
-
   // Normalize the url.
   std::string url_id = GetIdFromUrl(url);
 
   // Periodically garbage collect old entries.
   GarbageCollectEntriesIfNecessary();
 
   // Find the entry in the map or create it.
   UrlEntryMap::iterator i = url_entries_.find(url_id);
   if (i == url_entries_.end()) {
     scoped_refptr<URLRequestThrottlerEntry> entry(
@@ skipping 26 matching lines @@
 }
 
 void URLRequestThrottlerManager::EraseEntryForTests(const GURL& url) {
   // Normalize the url.
   std::string url_id = GetIdFromUrl(url);
   url_entries_.erase(url_id);
 }
 
 void URLRequestThrottlerManager::InitializeOptions(bool enforce_throttling) {
   enforce_throttling_ = enforce_throttling;
-  record_access_log_ = true;
 }
 
 URLRequestThrottlerManager::URLRequestThrottlerManager()
     : requests_since_last_gc_(0),
-      enforce_throttling_(true),
-      record_access_log_(false) {
+      enforce_throttling_(true) {
 }
 
 URLRequestThrottlerManager::~URLRequestThrottlerManager() {
   // Delete all entries.
   url_entries_.clear();
 }
 
 std::string URLRequestThrottlerManager::GetIdFromUrl(const GURL& url) const {
   if (!url.is_valid())
     return url.possibly_invalid_spec();
@@ skipping 14 matching lines @@
 void URLRequestThrottlerManager::GarbageCollectEntriesIfNecessary() {
   requests_since_last_gc_++;
   if (requests_since_last_gc_ < kRequestsBetweenCollecting)
     return;
 
   requests_since_last_gc_ = 0;
   GarbageCollectEntries();
 }
 
 void URLRequestThrottlerManager::GarbageCollectEntries() {
-  volatile AccessLog access_log_copy(access_log);
-
   // The more efficient way to remove outdated entries is iterating over all the
   // elements in the map, and removing those outdated ones during the process.
   // However, one hypothesis about the cause of crbug.com/71721 is that some
   // kind of iterator error happens when we change the map during iteration. As
   // a result, we write the code this way in order to track down the bug.
   std::list<std::string> outdated_keys;
   for (UrlEntryMap::iterator entry_iter = url_entries_.begin();
        entry_iter != url_entries_.end(); ++entry_iter) {
     std::string key = entry_iter->first;
     CHECK(entry_iter->second.get());
 
     if ((entry_iter->second)->IsEntryOutdated())
       outdated_keys.push_back(key);
   }
   for (std::list<std::string>::iterator key_iter = outdated_keys.begin();
        key_iter != outdated_keys.end(); ++key_iter) {
     url_entries_.erase(*key_iter);
   }
 
   // In case something broke we want to make sure not to grow indefinitely.
   while (url_entries_.size() > kMaximumNumberOfEntries) {
     url_entries_.erase(url_entries_.begin());
   }
 }
 
 }  // namespace net