Remove some unused history resources on iOS

ios/chrome/browser/ui/webui/history/metrics_handler.cc

-// Copyright 2016 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "ios/chrome/browser/ui/webui/history/metrics_handler.h"
-
-#include "base/bind.h"
-#include "base/bind_helpers.h"
-#include "base/logging.h"
-#include "base/metrics/histogram.h"
-#include "base/metrics/user_metrics.h"
-#include "base/strings/utf_string_conversions.h"
-#include "base/values.h"
-#include "ios/web/public/webui/web_ui_ios.h"
-
-using base::ListValue;
-using base::UserMetricsAction;
-
-MetricsHandler::MetricsHandler() {}
-MetricsHandler::~MetricsHandler() {}
-
-void MetricsHandler::RegisterMessages() {
-  web_ui()->RegisterMessageCallback(
-      "metricsHandler:recordAction",
-      base::Bind(&MetricsHandler::HandleRecordAction, base::Unretained(this)));
-  web_ui()->RegisterMessageCallback(
-      "metricsHandler:recordInHistogram",
-      base::Bind(&MetricsHandler::HandleRecordInHistogram,
-                 base::Unretained(this)));
-}
-
-void MetricsHandler::HandleRecordAction(const base::ListValue* args) {
-  std::string string_action = base::UTF16ToUTF8(ExtractStringValue(args));
-  base::RecordComputedAction(string_action);
-}
-
-void MetricsHandler::HandleRecordInHistogram(const base::ListValue* args) {
-  std::string histogram_name;
-  double value;
-  double boundary_value;
-  if (!args->GetString(0, &histogram_name) || !args->GetDouble(1, &value) ||
-      !args->GetDouble(2, &boundary_value)) {
-    NOTREACHED();
-    return;
-  }
-
-  int int_value = static_cast<int>(value);
-  int int_boundary_value = static_cast<int>(boundary_value);
-  if (int_boundary_value >= 4000 || int_value > int_boundary_value ||
-      int_value < 0) {
-    NOTREACHED();
-    return;
-  }
-
-  int bucket_count = int_boundary_value;
-  while (bucket_count >= 100) {
-    bucket_count /= 10;
-  }
-
-  // As |histogram_name| may change between calls, the UMA_HISTOGRAM_ENUMERATION
-  // macro cannot be used here.
-  base::HistogramBase* counter = base::LinearHistogram::FactoryGet(
-      histogram_name, 1, int_boundary_value, bucket_count + 1,
-      base::HistogramBase::kUmaTargetedHistogramFlag);
-  counter->Add(int_value);
-}