LBS: Synchronously load rules from prefs at first load

Bug: 1002307
Change-Id: Idb6c44387a7e8f89127610a8a7ac2524919ad145
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1802539Reviewed-by: Nicolas Ouellet-Payeur <nicolaso@chromium.org>
Commit-Queue: Yann Dago <ydago@chromium.org>
Cr-Commit-Position: refs/heads/master@{#696782}

chrome/browser/browser_switcher/browser_switcher_service.cc

@@ -230,12 +230,11 @@ BrowserSwitcherService::BrowserSwitcherService(Profile* profile)
 BrowserSwitcherService::~BrowserSwitcherService() = default;
 
 void BrowserSwitcherService::Init() {
+  LoadRulesFromPrefs();
   StartDownload(fetch_delay());
 }
 
 void BrowserSwitcherService::StartDownload(base::TimeDelta delay) {
-  LoadRulesFromPrefs();
-
   // This destroys the previous XmlDownloader, which cancels any scheduled
   // refresh operations.
   sitelist_downloader_ = std::make_unique<XmlDownloader>(

chrome/browser/browser_switcher/browser_switcher_service.h

@@ -148,6 +148,8 @@ class BrowserSwitcherService : public KeyedService {
   // happens.
   virtual void LoadRulesFromPrefs();
 
+  void Init();
+
  protected:
   virtual void OnAllRulesetsParsed();
   virtual void OnBrowserSwitcherPrefsChanged(
@@ -163,8 +165,6 @@ class BrowserSwitcherService : public KeyedService {
   // events and trigger a re-download immediately.
   friend class ::BrowserSwitchHandler;
 
-  void Init();
-
   void OnExternalSitelistParsed(ParsedXml xml);
   void OnExternalGreylistParsed(ParsedXml xml);
 

chrome/browser/browser_switcher/browser_switcher_service_factory.cc

@@ -50,7 +50,10 @@ BrowserSwitcherServiceFactory::~BrowserSwitcherServiceFactory() {}
 
 KeyedService* BrowserSwitcherServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
-  return new BrowserSwitcherServiceImpl(Profile::FromBrowserContext(context));
+  auto* instance =
+      new BrowserSwitcherServiceImpl(Profile::FromBrowserContext(context));
+  instance->Init();
+  return instance;
 }
 
 content::BrowserContext* BrowserSwitcherServiceFactory::GetBrowserContextToUse(