Revert of Change how the quota system computes the total poolsize for temporary storage

chrome/browser/engagement/site_engagement_eviction_policy.cc

Index: chrome/browser/engagement/site_engagement_eviction_policy.cc
diff --git a/chrome/browser/engagement/site_engagement_eviction_policy.cc b/chrome/browser/engagement/site_engagement_eviction_policy.cc
new file mode 100644
index 0000000000000000000000000000000000000000..7d52f566f2af035cb6230eee5c5835e32b035f56
--- /dev/null
+++ b/chrome/browser/engagement/site_engagement_eviction_policy.cc
@@ -0,0 +1,144 @@
+// 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_eviction_policy.h"
+
+#include "base/command_line.h"
+#include "base/metrics/field_trial.h"
+#include "base/strings/string_util.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/engagement/site_engagement_service.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/common/chrome_switches.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace {
+
+const int kExpectedEngagementSites = 200;
+
+// Gets the quota that an origin deserves based on its site engagement.
+int64_t GetSoftQuotaForOrigin(const GURL& origin,
+                              int score,
+                              int total_engagement_points,
+                              int64_t global_quota) {
+  double quota_per_point =
+      global_quota /
+      std::max(kExpectedEngagementSites * SiteEngagementService::GetMaxPoints(),
+               static_cast<double>(total_engagement_points));
+
+  return score * quota_per_point;
+}
+
+GURL DoCalculateEvictionOrigin(
+    const scoped_refptr<storage::SpecialStoragePolicy>& special_storage_policy,
+    SiteEngagementScoreProvider* score_provider,
+    const std::set<GURL>& exceptions,
+    const std::map<GURL, int64_t>& usage_map,
+    int64_t global_quota) {
+  // TODO(calamity): Integrate storage access frequency as an input to this
+  // heuristic.
+
+  // This heuristic is intended to optimize for two criteria:
+  // - evict the site that the user cares about least
+  // - evict the least number of sites to get under the quota limit
+  //
+  // The heuristic for deciding the next eviction origin calculates a soft
+  // quota for each origin which is the amount the origin should be allowed to
+  // use based on its engagement and the global quota. The origin that most
+  // exceeds its soft quota is chosen.
+  GURL origin_to_evict;
+  int64_t max_overuse = std::numeric_limits<int64_t>::min();
+  int total_engagement_points = score_provider->GetTotalEngagementPoints();
+
+  for (const auto& usage : usage_map) {
+    GURL origin = usage.first;
+    if (special_storage_policy &&
+        (special_storage_policy->IsStorageUnlimited(origin) ||
+         special_storage_policy->IsStorageDurable(origin))) {
+      continue;
+    }
+
+    // |overuse| can be negative if the soft quota exceeds the usage.
+    int64_t overuse =
+        usage.second -
+        GetSoftQuotaForOrigin(origin, score_provider->GetScore(origin),
+                              total_engagement_points, global_quota);
+    if (overuse > max_overuse && !base::ContainsKey(exceptions, origin)) {
+      max_overuse = overuse;
+      origin_to_evict = origin;
+    }
+  }
+
+  return origin_to_evict;
+}
+
+GURL GetSiteEngagementEvictionOriginOnUIThread(
+    const scoped_refptr<storage::SpecialStoragePolicy>& special_storage_policy,
+    content::BrowserContext* browser_context,
+    const std::set<GURL>& exceptions,
+    const std::map<GURL, int64_t>& usage_map,
+    int64_t global_quota) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
+  Profile* profile = Profile::FromBrowserContext(browser_context);
+  SiteEngagementScoreProvider* score_provider =
+      g_browser_process->profile_manager()->IsValidProfile(profile)
+          ? SiteEngagementService::Get(profile)
+          : nullptr;
+
+  if (!score_provider)
+    return GURL();
+
+  return DoCalculateEvictionOrigin(special_storage_policy, score_provider,
+                                   exceptions, usage_map, global_quota);
+}
+
+}  // namespace
+
+// static
+bool SiteEngagementEvictionPolicy::IsEnabled() {
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEnableSiteEngagementEvictionPolicy)) {
+    return true;
+  }
+
+  const std::string group_name = base::FieldTrialList::FindFullName(
+      SiteEngagementService::kEngagementParams);
+  return base::StartsWith(group_name, "StorageEvictionEnabled",
+                          base::CompareCase::SENSITIVE);
+}
+
+SiteEngagementEvictionPolicy::SiteEngagementEvictionPolicy(
+    content::BrowserContext* browser_context)
+    : browser_context_(browser_context) {}
+
+SiteEngagementEvictionPolicy::~SiteEngagementEvictionPolicy() {}
+
+void SiteEngagementEvictionPolicy::GetEvictionOrigin(
+    const scoped_refptr<storage::SpecialStoragePolicy>& special_storage_policy,
+    const std::set<GURL>& exceptions,
+    const std::map<GURL, int64_t>& usage_map,
+    int64_t global_quota,
+    const storage::GetOriginCallback& callback) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+
+  content::BrowserThread::PostTaskAndReplyWithResult(
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&GetSiteEngagementEvictionOriginOnUIThread,
+                 special_storage_policy, browser_context_, exceptions,
+                 usage_map, global_quota),
+      callback);
+}
+
+// static
+GURL SiteEngagementEvictionPolicy::CalculateEvictionOriginForTests(
+    const scoped_refptr<storage::SpecialStoragePolicy>& special_storage_policy,
+    SiteEngagementScoreProvider* score_provider,
+    const std::set<GURL>& exceptions,
+    const std::map<GURL, int64_t>& usage_map,
+    int64_t global_quota) {
+  return DoCalculateEvictionOrigin(special_storage_policy, score_provider,
+                                   exceptions, usage_map, global_quota);
+}