Convert ChromeViewHostMsg_UpdatedCacheStats to use mojo.

chrome/browser/cache_stats_recorder.cc

+// Copyright 2017 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 "chrome/browser/cache_stats_recorder.h"
+
+#include "base/memory/ptr_util.h"
+#include "components/web_cache/browser/web_cache_manager.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+
+CacheStatsRecorder::CacheStatsRecorder(int render_process_id)
+    : render_process_id_(render_process_id) {}
+
+CacheStatsRecorder::~CacheStatsRecorder() = default;
+
+// static
+void CacheStatsRecorder::Create(
+    int render_process_id,
+    chrome::mojom::CacheStatsRecorderRequest request) {
+  mojo::MakeStrongBinding(
+      base::MakeUnique<CacheStatsRecorder>(render_process_id),
+      std::move(request));
+}
+
+void CacheStatsRecorder::RecordCacheStats(uint64_t capacity, uint64_t size) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  web_cache::WebCacheManager::GetInstance()->ObserveStats(render_process_id_,

[sky, 2017/02/03 16:31:44]

Is there any concern that by the time this function is called the renderer
process id may no longer be valid? Do we at all care about recycling? I'm
wondering if CacheStatsRecorders should be destroyed if the renderer process is
destroyed.

+                                                          capacity, size);
+}