Remove unused blocking pool methods from web::WebThread.

ios/web/web_thread_impl.cc

Index: ios/web/web_thread_impl.cc
diff --git a/ios/web/web_thread_impl.cc b/ios/web/web_thread_impl.cc
index b6d082eeca64c24811324ac2333c109775e531d0..d1d6f415c6e70afc4f38c6cdcd2c4bc07abac2f9 100644
--- a/ios/web/web_thread_impl.cc
+++ b/ios/web/web_thread_impl.cc
@@ -330,31 +330,6 @@ bool WebThreadImpl::PostTaskHelper(WebThread::ID identifier,
 }
 
 // static
-bool WebThread::PostBlockingPoolTask(const tracked_objects::Location& from_here,
-                                     base::OnceClosure task) {
-  return g_globals.Get().blocking_pool->PostWorkerTask(from_here,
-                                                       std::move(task));
-}
-
-// static
-bool WebThread::PostBlockingPoolTaskAndReply(
-    const tracked_objects::Location& from_here,
-    base::OnceClosure task,
-    base::OnceClosure reply) {
-  return g_globals.Get().blocking_pool->PostTaskAndReply(
-      from_here, std::move(task), std::move(reply));
-}
-
-// static
-bool WebThread::PostBlockingPoolSequencedTask(
-    const std::string& sequence_token_name,
-    const tracked_objects::Location& from_here,
-    base::OnceClosure task) {
-  return g_globals.Get().blocking_pool->PostNamedSequencedWorkerTask(
-      sequence_token_name, from_here, std::move(task));
-}
-
-// static
 base::SequencedWorkerPool* WebThread::GetBlockingPool() {
   return g_globals.Get().blocking_pool.get();
 }