Add a SiteEngagementEvictionPolicy.

chrome/browser/engagement/site_engagement_service_proxy.cc

+// Copyright 2015 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/engagement/site_engagement_service.h"
+#include "chrome/browser/engagement/site_engagement_service_proxy.h"
+#include "chrome/browser/profiles/profile.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace {
+
+std::map<GURL, int> DoGetScoresForOrigins(
+    content::BrowserContext* browser_context,

[raymes, 2015/07/15 07:55:47]

We can't know for sure whether the browser_context is valid here.

[calamity, 2015/07/20 06:39:44]

We now check with the profile manager.

+    const std::vector<GURL>& origins) {
+  std::map<GURL, int> score_map;
+  SiteEngagementService* service =
+      SiteEngagementService::Get(Profile::FromBrowserContext(browser_context));
+  if (!service)
+    return score_map;
+
+  for (const auto& origin : origins)
+    score_map[origin] = service->GetScore(origin);
+
+  return score_map;
+}
+
+int DoGetTotalEngagementPoints(content::BrowserContext* browser_context) {
+  SiteEngagementService* service =
+      SiteEngagementService::Get(Profile::FromBrowserContext(browser_context));
+  return service ? service->GetTotalEngagementPoints() : 0;
+}
+
+}  // namespace
+
+SiteEngagementServiceProxy::SiteEngagementServiceProxy(
+    content::BrowserContext* browser_context)
+    : browser_context_(browser_context) {
+}
+
+SiteEngagementServiceProxy::~SiteEngagementServiceProxy() {
+}
+
+void SiteEngagementServiceProxy::GetScoresForOrigins(
+    const std::vector<GURL>& origins,
+    base::Callback<void(const std::map<GURL, int>&)> callback) {
+  content::BrowserThread::PostTaskAndReplyWithResult(
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&DoGetScoresForOrigins, browser_context_, origins), callback);
+}
+
+void SiteEngagementServiceProxy::GetTotalEngagementPoints(
+    base::Callback<void(int)> callback) {
+  content::BrowserThread::PostTaskAndReplyWithResult(
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&DoGetTotalEngagementPoints, browser_context_), callback);
+}