[Most Visited] Check for Sync state when using SuggestionsService.

components/suggestions/suggestions_service.cc

 // Copyright 2014 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 "components/suggestions/suggestions_service.h"
 
 #include <sstream>
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 138 matching lines @@
          kSuggestionsFieldTrialStateEnabled;
 }
 
 // static
 bool SuggestionsService::IsControlGroup() {
   return GetExperimentParam(kSuggestionsFieldTrialControlParam) ==
          kSuggestionsFieldTrialStateEnabled;
 }
 
 void SuggestionsService::FetchSuggestionsData(
+    bool sync_initialized,
+    bool history_sync_enabled,
     SuggestionsService::ResponseCallback callback) {
   DCHECK(thread_checker_.CalledOnValidThread());
+  if (!sync_initialized) {
+    // Serve from cache.
+    waiting_requestors_.push_back(callback);
+    ServeFromCache();
+    return;
+  } else if (!history_sync_enabled) {
+    // User hasn't enabled history sync.
+    callback.Run(SuggestionsProfile());

[manzagop (departed), 2014/08/15 13:01:52]

Why not clear the cache, then push back requestors and serve from cache?

You need to clear the cache so we "remember" it's disabled. Otherwise you'll
serve the suggestions the next time you're uninitialized.

[Mathieu, 2014/08/20 14:21:32]

Done.

+    return;
+  }
+  // Sync is initialized and history sync is enabled.
 
   FetchSuggestionsDataNoTimeout(callback);
 
   // Post a task to serve the cached suggestions if the request hasn't completed
   // after some time. Cancels the previous such task, if one existed.
   pending_timeout_closure_.reset(new CancelableClosure(base::Bind(
       &SuggestionsService::OnRequestTimeout, weak_ptr_factory_.GetWeakPtr())));
   base::MessageLoopProxy::current()->PostDelayedTask(
       FROM_HERE, pending_timeout_closure_->callback(),
       base::TimeDelta::FromMilliseconds(request_timeout_ms_));
@@ skipping 228 matching lines @@
   if (last_request_successful) {
     blacklist_delay_sec_ = kBlacklistDefaultDelaySec;
   } else {
     int candidate_delay = blacklist_delay_sec_ * kBlacklistBackoffMultiplier;
     if (candidate_delay < kBlacklistMaxDelaySec)
       blacklist_delay_sec_ = candidate_delay;
   }
 }
 
 }  // namespace suggestions