Pass pipeline failure reason to a transition event

app/models/ci/pipeline.rb

@@ -126,6 +126,12 @@ module Ci
         pipeline.auto_canceled_by = nil
       end
 
+      before_transition any => :failed do |pipeline, transition|
+        transition.args.first.try do |reason|
+          pipeline.failure_reason = reason
+        end
+      end
+
       after_transition [:created, :pending] => :running do |pipeline|
         pipeline.run_after_commit { PipelineMetricsWorker.perform_async(pipeline.id) }
       end

ee/lib/ee/gitlab/ci/pipeline/chain/limit/activity.rb

@@ -21,8 +21,7 @@ module EE
                 @pipeline.cancel_running
 
                 retry_optimistic_lock(@pipeline) do
-                  @pipeline.failure_reason = :activity_limit_exceeded
-                  @pipeline.drop!
+                  @pipeline.drop!(:activity_limit_exceeded)
                 end
 
                 # TODO, should we invalidate the pipeline

ee/lib/ee/gitlab/ci/pipeline/chain/limit/size.rb

@@ -18,8 +18,7 @@ module EE
                 return unless @limit.exceeded?
 
                 if @command.save_incompleted
-                  @pipeline.failure_reason = :size_limit_exceeded
-                  @pipeline.drop
+                  @pipeline.drop!(:size_limit_exceeded)
                 end
 
                 error(@limit.message)