Remove dead flush histograms code.

content/child/child_histogram_message_filter.cc

Index: content/child/child_histogram_message_filter.cc
diff --git a/content/child/child_histogram_message_filter.cc b/content/child/child_histogram_message_filter.cc
index 0daa7f3f423c1a56f5ac580cb107ac2cc7e72169..8551b6afdd6e070b0acc71a62a03632ecfd74e7c 100644
--- a/content/child/child_histogram_message_filter.cc
+++ b/content/child/child_histogram_message_filter.cc
@@ -60,12 +60,6 @@ void ChildHistogramMessageFilter::OnSetHistogramMemory(
     global_allocator->CreateTrackingHistograms(global_allocator->Name());
 }
 
-void ChildHistogramMessageFilter::SendHistograms(int sequence_number) {
-  io_task_runner_->PostTask(
-      FROM_HERE, base::Bind(&ChildHistogramMessageFilter::UploadAllHistograms,
-                            this, sequence_number));
-}
-
 void ChildHistogramMessageFilter::OnGetChildHistogramData(int sequence_number) {
   UploadAllHistograms(sequence_number);
 }