[fuchsia] Remove Agent::RunTask method

Fuchsia is removing RunTask and must remove all external references first.

Bug: 1019980
Change-Id: I95db4ae011e6dab6755af93a795f359b764ceacf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1890732Reviewed-by: Wez <wez@chromium.org>
Commit-Queue: Rich Kadel <richkadel@google.com>
Auto-Submit: Rich Kadel <richkadel@google.com>
Cr-Commit-Position: refs/heads/master@{#711068}

fuchsia/base/agent_impl.cc

@@ -80,11 +80,6 @@ void AgentImpl::Connect(
   it->second->service_provider_->AddBinding(std::move(services));
 }
 
-void AgentImpl::RunTask(std::string task_id, RunTaskCallback callback) {
-  NOTIMPLEMENTED();
-  callback();
-}
-
 void AgentImpl::DeleteComponentState(base::StringPiece component_id) {
   size_t removed_components = active_components_.erase(component_id);
   DCHECK_EQ(removed_components, 1u);

fuchsia/base/agent_impl.h

@@ -115,7 +115,6 @@ class AgentImpl : public ::fuchsia::modular::Agent {
   void Connect(std::string requester_url,
                fidl::InterfaceRequest<::fuchsia::sys::ServiceProvider> services)
       override;
-  void RunTask(std::string task_id, RunTaskCallback callback) override;
 
  private:
   friend class ComponentStateBase;