Initialize ios/web_view translate with a system-wide URLRequestContext.

ios/web_view/internal/app/application_context.cc

+// Copyright 2017 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 "ios/web_view/internal/app/application_context.h"
+
+#include "base/command_line.h"
+#include "base/memory/ptr_util.h"
+#include "base/memory/singleton.h"
+#include "base/path_service.h"
+#include "base/tracked_objects.h"
+#include "components/flags_ui/pref_service_flags_storage.h"
+#include "components/net_log/chrome_net_log.h"
+#include "components/prefs/json_pref_store.h"
+#include "components/prefs/pref_registry_simple.h"
+#include "components/prefs/pref_service.h"
+#include "components/prefs/pref_service_factory.h"
+#include "components/proxy_config/pref_proxy_config_tracker_impl.h"
+#include "components/ssl_config/ssl_config_service_manager.h"
+#include "components/translate/core/browser/translate_download_manager.h"
+#include "ios/web/public/web_thread.h"
+#include "ios/web_view/internal/app/web_view_io_thread.h"
+#include "net/socket/client_socket_pool_manager.h"
+#include "ui/base/l10n/l10n_util_mac.h"
+
+namespace ios_web_view {
+
+ApplicationContext* ApplicationContext::GetInstance() {
+  return base::Singleton<ApplicationContext>::get();
+}
+
+ApplicationContext::ApplicationContext()
+    : local_state_task_runner_(JsonPrefStore::GetTaskRunnerForFile(
+          GetLocalStatePath(),
+          web::WebThread::GetBlockingPool())) {
+  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+
+  net_log_ = base::MakeUnique<net_log::ChromeNetLog>(
+      base::FilePath(), net::NetLogCaptureMode::Default(),
+      command_line->GetCommandLineString(), std::string());
+
+  SetApplicationLocale(l10n_util::GetLocaleOverride());
+}
+
+ApplicationContext::~ApplicationContext() {
+  tracked_objects::ThreadData::EnsureCleanupWasCalled(4);

[Eugene But (OOO till 7-30), 2017/05/31 16:25:33]

Could you please create a constant for "4" with explanation why it is 4.

[michaeldo, 2017/05/31 21:03:42]

I deleted this instead. There is no sense in adding another call to this method
as it is dead code. (I asked //base owners and got one agreement so I don't
think we need this in here at all.) I will remove other calls like this if I get
a chance. In the meantime I filed crbug.com/728299.

+}
+
+void ApplicationContext::PreCreateThreads() {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  web_view_io_thread_ =
+      base::MakeUnique<WebViewIOThread>(GetLocalState(), GetNetLog());
+}
+
+void ApplicationContext::SaveState() {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  // TODO(crbug.com/723854): Commit prefs when entering background.
+  if (local_state_) {

[Eugene But (OOO till 7-30), 2017/05/31 16:25:33]

Should we create local_state_ instead of having no-op behavior? If no, could you
please clarify the reason in the comments.

[michaeldo, 2017/05/31 21:03:42]

I don't think so. No reason to create Local state as there won't be any pending
writes. I've updated the comment in the header.

+    local_state_->CommitPendingWrite();
+  }
+}
+
+void ApplicationContext::PostDestroyThreads() {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  // Resets associated state right after actual thread is stopped as
+  // WebViewIOThread::Globals cleanup happens in CleanUp on the IO
+  // thread, i.e. as the thread exits its message loop.
+  //
+  // This is important because in various places, the WebViewIOThread
+  // object being null is considered synonymous with the IO thread
+  // having stopped.
+  web_view_io_thread_.reset();
+}
+
+PrefService* ApplicationContext::GetLocalState() {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  if (!local_state_) {
+    // Register local state preferences.
+    scoped_refptr<PrefRegistrySimple> pref_registry(new PrefRegistrySimple);
+    flags_ui::PrefServiceFlagsStorage::RegisterPrefs(pref_registry.get());
+    PrefProxyConfigTrackerImpl::RegisterPrefs(pref_registry.get());
+    ssl_config::SSLConfigServiceManager::RegisterPrefs(pref_registry.get());
+
+    scoped_refptr<PersistentPrefStore> user_pref_store = new JsonPrefStore(
+        GetLocalStatePath(), local_state_task_runner_, nullptr);
+
+    PrefServiceFactory factory;
+    factory.set_user_prefs(user_pref_store);
+    local_state_ = factory.Create(pref_registry.get());
+
+    int max_normal_socket_pool_count =
+        net::ClientSocketPoolManager::max_sockets_per_group(
+            net::HttpNetworkSession::NORMAL_SOCKET_POOL);
+    int socket_count =
+        std::max(std::min<int>(net::kDefaultMaxSocketsPerProxyServer, 99),

[Eugene But (OOO till 7-30), 2017/05/31 16:25:34]

Do we know why we limit to 99 sockets?

[michaeldo, 2017/05/31 21:03:42]

Unfortunately, I have no idea. I don't think it's beneficial for me to guess,
but I will look through commit history to see if I can find an original reason
for the constant.

[Hiroshi Ichikawa, 2017/06/01 02:25:59]

Can you at least add a comment which points to where this comes from (i.e., the
original code location)?

[michaeldo, 2017/06/01 21:20:38]

I started to add a comment, but then looked into this more and simply removed
the 99 and the std::min. There is a DCHECK inside
|set_max_sockets_per_proxy_server| if the |socket_count| is greater than 100 so
I don't think this 99 is necessary. Also, net::kDefaultMaxSocketsPerProxyServer
hasn't changed in 6 years and if it does, the internals of that class will end
up being adjusted accordingly.

+                 max_normal_socket_pool_count);
+    net::ClientSocketPoolManager::set_max_sockets_per_proxy_server(
+        net::HttpNetworkSession::NORMAL_SOCKET_POOL, socket_count);
+  }
+  return local_state_.get();
+}
+
+net::URLRequestContextGetter* ApplicationContext::GetSystemURLRequestContext() {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  return web_view_io_thread_->system_url_request_context_getter();
+}
+
+const std::string& ApplicationContext::GetApplicationLocale() {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  DCHECK(!application_locale_.empty());
+  return application_locale_;
+}
+
+net_log::ChromeNetLog* ApplicationContext::GetNetLog() {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  return net_log_.get();
+}
+
+WebViewIOThread* ApplicationContext::GetWebViewIOThread() {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  DCHECK(web_view_io_thread_.get());
+  return web_view_io_thread_.get();
+}
+
+base::FilePath ApplicationContext::GetLocalStatePath() {
+  base::FilePath local_state_path;
+  PathService::Get(base::DIR_APP_DATA, &local_state_path);
+  local_state_path =
+      local_state_path.Append(FILE_PATH_LITERAL("ChromeWebView"));
+  local_state_path = local_state_path.Append(FILE_PATH_LITERAL("Local State"));
+  return local_state_path;
+}
+
+void ApplicationContext::SetApplicationLocale(const std::string& locale) {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+  application_locale_ = locale;
+  translate::TranslateDownloadManager::GetInstance()->set_application_locale(
+      application_locale_);
+}
+
+}  // namespace ios_web_view