Fix build error with gcc 4.8.2 about WARN_UNUSED_RESULT

For static methods it does not seem to work properly with older gcc.
Indeed the compiler consider the result as not used in this example:

sequence_token_ = BrowserThread::GetBlockingPool()->GetSequenceToken()

"error: ignoring return value of 'static base::SequencedWorkerPool*
content::BrowserThread::GetBlockingPool()', declared with attribute
warn_unused_result [-Werror=unused-result]"

The solution is just to call GetSequenceToken() directly as:
base::SequencedWorkerPool::GetSequenceToken() as it is static.

BUG=579461

R=cpu@chromium.org, nico@chromium.org

TEST= GYP_DEFINES="clang=0 use_sysroot=0"

Review URL: https://codereview.chromium.org/1610103002

Cr-Commit-Position: refs/heads/master@{#371479}

chrome/browser/component_updater/chrome_component_updater_configurator.cc

@@ -131,7 +131,7 @@ scoped_refptr<base::SequencedTaskRunner>
 ChromeConfigurator::GetSequencedTaskRunner() const {
   return content::BrowserThread::GetBlockingPool()
       ->GetSequencedTaskRunnerWithShutdownBehavior(
-          content::BrowserThread::GetBlockingPool()->GetSequenceToken(),
+          base::SequencedWorkerPool::GetSequenceToken(),
           base::SequencedWorkerPool::CONTINUE_ON_SHUTDOWN);
 }
 

chrome/browser/dom_distiller/dom_distiller_service_factory.cc

@@ -55,7 +55,7 @@ KeyedService* DomDistillerServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* profile) const {
   scoped_refptr<base::SequencedTaskRunner> background_task_runner =
       content::BrowserThread::GetBlockingPool()->GetSequencedTaskRunner(
-          content::BrowserThread::GetBlockingPool()->GetSequenceToken());
+          base::SequencedWorkerPool::GetSequenceToken());
 
   scoped_ptr<leveldb_proto::ProtoDatabaseImpl<ArticleEntry> > db(
       new leveldb_proto::ProtoDatabaseImpl<ArticleEntry>(

chrome/browser/profiles/profile_impl_io_data.cc

@@ -508,7 +508,7 @@ void ProfileImplIOData::InitializeInternal(
         new QuotaPolicyChannelIDStore(
             lazy_params_->channel_id_path,
             BrowserThread::GetBlockingPool()->GetSequencedTaskRunner(
-                BrowserThread::GetBlockingPool()->GetSequenceToken()),
+                base::SequencedWorkerPool::GetSequenceToken()),
             lazy_params_->special_storage_policy.get());
     channel_id_service = new net::ChannelIDService(
         new net::DefaultChannelIDStore(channel_id_db.get()),

chrome/browser/search/suggestions/suggestions_service_factory.cc

@@ -57,7 +57,7 @@ KeyedService* SuggestionsServiceFactory::BuildServiceInstanceFor(
     content::BrowserContext* profile) const {
   scoped_refptr<base::SequencedTaskRunner> background_task_runner =
       BrowserThread::GetBlockingPool()->GetSequencedTaskRunner(
-          BrowserThread::GetBlockingPool()->GetSequenceToken());
+          base::SequencedWorkerPool::GetSequenceToken());
 
   Profile* the_profile = static_cast<Profile*>(profile);
 

components/visitedlink/browser/visitedlink_master.cc

@@ -282,7 +282,7 @@ void VisitedLinkMaster::InitMembers() {
   used_items_ = 0;
   table_size_override_ = 0;
   suppress_rebuild_ = false;
-  sequence_token_ = BrowserThread::GetBlockingPool()->GetSequenceToken();
+  sequence_token_ = base::SequencedWorkerPool::GetSequenceToken();
 }
 
 bool VisitedLinkMaster::Init() {

extensions/browser/updater/update_client_config.cc

@@ -14,7 +14,7 @@ scoped_refptr<base::SequencedTaskRunner>
 UpdateClientConfig::GetSequencedTaskRunner() const {
   return content::BrowserThread::GetBlockingPool()
       ->GetSequencedTaskRunnerWithShutdownBehavior(
-          content::BrowserThread::GetBlockingPool()->GetSequenceToken(),
+          base::SequencedWorkerPool::GetSequenceToken(),
           base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
 }