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

storage/browser/quota/quota_manager.cc

Index: storage/browser/quota/quota_manager.cc
diff --git a/storage/browser/quota/quota_manager.cc b/storage/browser/quota/quota_manager.cc
index 44ba5f1019d3833427b24a81568fddd3afe5ac0b..3b91f706711df189290053f6d1f8e2365c6b2cb6 100644
--- a/storage/browser/quota/quota_manager.cc
+++ b/storage/browser/quota/quota_manager.cc
@@ -13,6 +13,7 @@
 #include <memory>
 #include <utility>
 
+#include "base/barrier_closure.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
@@ -26,6 +27,7 @@
 #include "base/strings/string_number_conversions.h"
 #include "base/sys_info.h"
 #include "base/task_runner_util.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
 #include "net/base/url_util.h"
@@ -36,49 +38,37 @@
 #include "storage/browser/quota/usage_tracker.h"
 #include "storage/common/quota/quota_types.h"
 
-#define UMA_HISTOGRAM_MBYTES(name, sample)          \
-  UMA_HISTOGRAM_CUSTOM_COUNTS(                      \
-      (name), static_cast<int>((sample) / kMBytes), \
-      1, 10 * 1024 * 1024 /* 10TB */, 100)
-
 namespace storage {
 
 namespace {
 
 const int64_t kMBytes = 1024 * 1024;
 const int kMinutesInMilliSeconds = 60 * 1000;
-
 const int64_t kReportHistogramInterval = 60 * 60 * 1000;  // 1 hour
-const double kTemporaryQuotaRatioToAvail = 1.0 / 3.0;  // 33%
 
-}  // namespace
+#define UMA_HISTOGRAM_MBYTES(name, sample)          \
+  UMA_HISTOGRAM_CUSTOM_COUNTS(                      \
+      (name), static_cast<int>((sample) / kMBytes), \
+      1, 10 * 1024 * 1024 /* 10TB */, 100)
 
-// Arbitrary for now, but must be reasonably small so that
-// in-memory databases can fit.
-// TODO(kinuko): Refer SysInfo::AmountOfPhysicalMemory() to determine this.
-const int64_t QuotaManager::kIncognitoDefaultQuotaLimit = 100 * kMBytes;
+}  // namespace
 
 const int64_t QuotaManager::kNoLimit = INT64_MAX;
 
-const int QuotaManager::kPerHostTemporaryPortion = 5;  // 20%
-
 // Cap size for per-host persistent quota determined by the histogram.
 // This is a bit lax value because the histogram says nothing about per-host
 // persistent storage usage and we determined by global persistent storage
 // usage that is less than 10GB for almost all users.
 const int64_t QuotaManager::kPerHostPersistentQuotaLimit = 10 * 1024 * kMBytes;
 
+// Heuristics: assuming average cloud server allows a few Gigs storage
+// on the server side and the storage needs to be shared for user data
+// and by multiple apps.
+int64_t QuotaManager::kSyncableStorageDefaultHostQuota = 500 * kMBytes;
+
 const char QuotaManager::kDatabaseName[] = "QuotaManager";
 
 const int QuotaManager::kThresholdOfErrorsToBeBlacklisted = 3;
-
-// Preserve kMinimumPreserveForSystem disk space for system book-keeping
-// when returning the quota to unlimited apps/extensions.
-// TODO(kinuko): This should be like 10% of the actual disk space.
-// For now we simply use a constant as getting the disk size needs
-// platform-dependent code. (http://crbug.com/178976)
-int64_t QuotaManager::kMinimumPreserveForSystem = 1024 * kMBytes;
-
 const int QuotaManager::kEvictionIntervalInMilliSeconds =
     30 * kMinutesInMilliSeconds;
 
@@ -89,11 +79,6 @@ const char QuotaManager::kEvictedOriginAccessedCountHistogram[] =
 const char QuotaManager::kEvictedOriginTimeSinceAccessHistogram[] =
     "Quota.EvictedOriginTimeSinceAccess";
 
-// Heuristics: assuming average cloud server allows a few Gigs storage
-// on the server side and the storage needs to be shared for user data
-// and by multiple apps.
-int64_t QuotaManager::kSyncableStorageDefaultHostQuota = 500 * kMBytes;
-
 namespace {
 
 void CountOriginType(const std::set<GURL>& origins,
@@ -116,17 +101,6 @@ void CountOriginType(const std::set<GURL>& origins,
   }
 }
 
-bool SetTemporaryGlobalOverrideQuotaOnDBThread(int64_t* new_quota,
-                                               QuotaDatabase* database) {
-  DCHECK(database);
-  if (!database->SetQuotaConfigValue(
-          QuotaDatabase::kTemporaryQuotaOverrideKey, *new_quota)) {
-    *new_quota = -1;
-    return false;
-  }
-  return true;
-}
-
 bool GetPersistentHostQuotaOnDBThread(const std::string& host,
                                       int64_t* quota,
                                       QuotaDatabase* database) {
@@ -145,17 +119,6 @@ bool SetPersistentHostQuotaOnDBThread(const std::string& host,
   return false;
 }
 
-bool InitializeOnDBThread(int64_t* temporary_quota_override,
-                          int64_t* desired_available_space,
-                          QuotaDatabase* database) {
-  DCHECK(database);
-  database->GetQuotaConfigValue(QuotaDatabase::kTemporaryQuotaOverrideKey,
-                                temporary_quota_override);
-  database->GetQuotaConfigValue(QuotaDatabase::kDesiredAvailableSpaceKey,
-                                desired_available_space);
-  return true;
-}
-
 bool GetLRUOriginOnDBThread(StorageType type,
                             const std::set<GURL>& exceptions,
                             SpecialStoragePolicy* policy,
@@ -204,8 +167,8 @@ bool DeleteOriginInfoOnDBThread(const GURL& origin,
   return database->SetOriginLastEvictionTime(origin, type, now);
 }
 
-bool InitializeTemporaryOriginsInfoOnDBThread(const std::set<GURL>* origins,
-                                              QuotaDatabase* database) {
+bool BootstrapDatabaseOnDBThread(const std::set<GURL>* origins,
+                                 QuotaDatabase* database) {
   DCHECK(database);
   if (database->IsOriginDatabaseBootstrapped())
     return true;
@@ -234,277 +197,222 @@ bool UpdateModifiedTimeOnDBThread(const GURL& origin,
   return database->SetOriginLastModifiedTime(origin, type, modified_time);
 }
 
-int64_t CalculateTemporaryGlobalQuota(int64_t global_limited_usage,
-                                      int64_t available_space) {
-  DCHECK_GE(global_limited_usage, 0);
-  int64_t avail_space = available_space;
-  if (avail_space <
-      std::numeric_limits<int64_t>::max() - global_limited_usage) {
-    // We basically calculate the temporary quota by
-    // [available_space + space_used_for_temp] * kTempQuotaRatio,
-    // but make sure we'll have no overflow.
-    avail_space += global_limited_usage;
-  }
-  int64_t pool_size = avail_space * kTemporaryQuotaRatioToAvail;
-  UMA_HISTOGRAM_MBYTES("Quota.GlobalTemporaryPoolSize", pool_size);
-  return pool_size;
-}
-
-void DispatchTemporaryGlobalQuotaCallback(
-    const QuotaCallback& callback,
-    QuotaStatusCode status,
-    const UsageAndQuota& usage_and_quota) {
-  if (status != kQuotaStatusOk) {
-    callback.Run(status, 0);
-    return;
-  }
-
-  callback.Run(status, CalculateTemporaryGlobalQuota(
-      usage_and_quota.global_limited_usage,
-      usage_and_quota.available_disk_space));
-}
-
-int64_t CalculateQuotaWithDiskSpace(int64_t available_disk_space,
-                                    int64_t usage,
-                                    int64_t quota) {
-  if (available_disk_space < QuotaManager::kMinimumPreserveForSystem) {
-    LOG(WARNING)
-        << "Running out of disk space for profile."
-        << " QuotaManager starts forbidding further quota consumption.";
-    return usage;
-  }
-
-  if (quota < usage) {
-    // No more space; cap the quota to the current usage.
-    return usage;
-  }
-
-  available_disk_space -= QuotaManager::kMinimumPreserveForSystem;
-  if (available_disk_space < quota - usage)
-    return available_disk_space + usage;
-
-  return quota;
-}
-
-int64_t CalculateTemporaryHostQuota(int64_t host_usage,
-                                    int64_t global_quota,
-                                    int64_t global_limited_usage) {
-  DCHECK_GE(global_limited_usage, 0);
-  int64_t host_quota = global_quota / QuotaManager::kPerHostTemporaryPortion;
-  if (global_limited_usage > global_quota)
-    host_quota = std::min(host_quota, host_usage);
-  return host_quota;
-}
-
-void DispatchUsageAndQuotaForWebApps(
-    StorageType type,
-    bool is_incognito,
-    bool is_unlimited,
-    bool can_query_disk_size,
-    const QuotaManager::GetUsageAndQuotaCallback& callback,
-    QuotaStatusCode status,
-    const UsageAndQuota& usage_and_quota) {
-  if (status != kQuotaStatusOk) {
-    callback.Run(status, 0, 0);
-    return;
-  }
-
-  int64_t usage = usage_and_quota.usage;
-  int64_t quota = usage_and_quota.quota;
-
-  if (type == kStorageTypeTemporary && !is_unlimited) {
-    quota = CalculateTemporaryHostQuota(
-        usage, quota, usage_and_quota.global_limited_usage);
-  }
-
-  if (is_incognito) {
-    quota = std::min(quota, QuotaManager::kIncognitoDefaultQuotaLimit);
-    callback.Run(status, usage, quota);
-    return;
-  }
-
-  // For apps with unlimited permission or can_query_disk_size is true (and not
-  // in incognito mode).
-  // We assume we can expose the actual disk size for them and cap the quota by
-  // the available disk space.
-  if (is_unlimited || can_query_disk_size) {
-    quota = CalculateQuotaWithDiskSpace(
-        usage_and_quota.available_disk_space,
-        usage, quota);
-  }
-
-  callback.Run(status, usage, quota);
-
-  if (type == kStorageTypeTemporary && !is_unlimited)
-    UMA_HISTOGRAM_MBYTES("Quota.QuotaForOrigin", quota);
-}
-
 }  // namespace
 
-UsageAndQuota::UsageAndQuota()
-    : usage(0),
-      global_limited_usage(0),
-      quota(0),
-      available_disk_space(0) {
-}
-
-UsageAndQuota::UsageAndQuota(int64_t usage,
-                             int64_t global_limited_usage,
-                             int64_t quota,
-                             int64_t available_disk_space)
-    : usage(usage),
-      global_limited_usage(global_limited_usage),
-      quota(quota),
-      available_disk_space(available_disk_space) {}
-
-class UsageAndQuotaCallbackDispatcher
-    : public QuotaTask,
-      public base::SupportsWeakPtr<UsageAndQuotaCallbackDispatcher> {
+class QuotaManager::UsageAndQuotaHelper : public QuotaTask {
  public:
-  explicit UsageAndQuotaCallbackDispatcher(QuotaManager* manager)
+  UsageAndQuotaHelper(QuotaManager* manager,
+                      const GURL& origin,
+                      StorageType type,
+                      bool is_unlimited,
+                      bool is_incognito,
+                      const UsageAndQuotaCallback& callback)
       : QuotaTask(manager),
-        has_usage_(false),
-        has_global_limited_usage_(false),
-        has_quota_(false),
-        has_available_disk_space_(false),
-        status_(kQuotaStatusUnknown),
-        usage_and_quota_(-1, -1, -1, -1),
-        waiting_callbacks_(1) {}
-
-  ~UsageAndQuotaCallbackDispatcher() override {}
-
-  void WaitForResults(const QuotaManager::UsageAndQuotaCallback& callback) {
-    callback_ = callback;
-    Start();
-  }
-
-  void set_usage(int64_t usage) {
-    usage_and_quota_.usage = usage;
-    has_usage_ = true;
-  }
-
-  void set_global_limited_usage(int64_t global_limited_usage) {
-    usage_and_quota_.global_limited_usage = global_limited_usage;
-    has_global_limited_usage_ = true;
-  }
+        origin_(origin),
+        callback_(callback),
+        type_(type),
+        is_unlimited_(is_unlimited),
+        is_incognito_(is_incognito),
+        weak_factory_(this) {}
 
-  void set_quota(int64_t quota) {
-    usage_and_quota_.quota = quota;
-    has_quota_ = true;
+ protected:
+  void Run() override {
+    // Start the async process of gathering the info we need.
+    // Gather 4 pieces of info before computing an answer:
+    // settings, device_storage_capacity, host_usage, and host_quota.
+    base::Closure barrier = base::BarrierClosure(
+        4, base::Bind(&UsageAndQuotaHelper::OnBarrierComplete,
+                      weak_factory_.GetWeakPtr()));
+
+    std::string host = net::GetHostOrSpecFromURL(origin_);
+
+    manager()->GetQuotaSettings(base::Bind(&UsageAndQuotaHelper::OnGotSettings,
+                                           weak_factory_.GetWeakPtr(),
+                                           barrier));
+    manager()->GetStorageCapacity(
+        base::Bind(&UsageAndQuotaHelper::OnGotCapacity,
+                   weak_factory_.GetWeakPtr(), barrier));
+    manager()->GetHostUsage(host, type_,
+                            base::Bind(&UsageAndQuotaHelper::OnGotHostUsage,
+                                       weak_factory_.GetWeakPtr(), barrier));
+
+    // Determine host_quota differently depending on type.
+    if (is_unlimited_) {
+      SetDesiredHostQuota(barrier, kQuotaStatusOk, kNoLimit);
+    } else if (type_ == kStorageTypeSyncable) {
+      SetDesiredHostQuota(barrier, kQuotaStatusOk,
+                          kSyncableStorageDefaultHostQuota);
+    } else if (type_ == kStorageTypePersistent) {
+      manager()->GetPersistentHostQuota(
+          host, base::Bind(&UsageAndQuotaHelper::SetDesiredHostQuota,
+                           weak_factory_.GetWeakPtr(), barrier));
+    } else {
+      DCHECK_EQ(kStorageTypeTemporary, type_);
+      // For temporary storge,  OnGotSettings will set the host quota.
+    }
   }
 
-  void set_available_disk_space(int64_t available_disk_space) {
-    usage_and_quota_.available_disk_space = available_disk_space;
-    has_available_disk_space_ = true;
+  void Aborted() override {
+    weak_factory_.InvalidateWeakPtrs();
+    callback_.Run(kQuotaErrorAbort, 0, 0);
+    DeleteSoon();
   }
 
-  UsageCallback GetHostUsageCallback() {
-    ++waiting_callbacks_;
-    has_usage_ = true;
-    return base::Bind(&UsageAndQuotaCallbackDispatcher::DidGetHostUsage,
-                      AsWeakPtr());
+  void Completed() override {
+    weak_factory_.InvalidateWeakPtrs();
+
+    // Constrain the desired |host_quota| to something that fits.
+    // If available space is too low, cap usage at current levels.
+    // If it's close to being too low, cap growth to avoid it getting too low.
+    int64_t host_quota =
+        std::min(desired_host_quota_,
+                 host_usage_ +
+                     std::max(INT64_C(0), available_space_ -
+                                              settings_.must_remain_available));
+    callback_.Run(kQuotaStatusOk, host_usage_, host_quota);
+    if (type_ == kStorageTypeTemporary && !is_incognito_ && !is_unlimited_)
+      UMA_HISTOGRAM_MBYTES("Quota.QuotaForOrigin", host_quota);
+    DeleteSoon();
   }
 
-  UsageCallback GetGlobalLimitedUsageCallback() {
-    ++waiting_callbacks_;
-    has_global_limited_usage_ = true;
-    return base::Bind(
-        &UsageAndQuotaCallbackDispatcher::DidGetGlobalLimitedUsage,
-        AsWeakPtr());
+ private:
+  QuotaManager* manager() const {
+    return static_cast<QuotaManager*>(observer());
   }
 
-  QuotaCallback GetQuotaCallback() {
-    ++waiting_callbacks_;
-    has_quota_ = true;
-    return base::Bind(&UsageAndQuotaCallbackDispatcher::DidGetQuota,
-                      AsWeakPtr());
+  void OnGotSettings(const base::Closure& barrier_closure,
+                     const QuotaSettings& settings) {
+    settings_ = settings;
+    barrier_closure.Run();
+    if (type_ == kStorageTypeTemporary && !is_unlimited_) {
+      SetDesiredHostQuota(barrier_closure, kQuotaStatusOk,
+                          settings.per_host_quota);
+    }
   }
 
-  QuotaCallback GetAvailableSpaceCallback() {
-    ++waiting_callbacks_;
-    has_available_disk_space_ = true;
-    return base::Bind(&UsageAndQuotaCallbackDispatcher::DidGetAvailableSpace,
-                      AsWeakPtr());
+  void OnGotCapacity(const base::Closure& barrier_closure,
+                     int64_t total_space,
+                     int64_t available_space) {
+    total_space_ = total_space;
+    available_space_ = available_space;
+    barrier_closure.Run();
   }
 
- private:
-  void DidGetHostUsage(int64_t usage) {
-    if (status_ == kQuotaStatusUnknown)
-      status_ = kQuotaStatusOk;
-    usage_and_quota_.usage = usage;
-    CheckCompleted();
+  void OnGotHostUsage(const base::Closure& barrier_closure, int64_t usage) {
+    host_usage_ = usage;
+    barrier_closure.Run();
   }
 
-  void DidGetGlobalLimitedUsage(int64_t limited_usage) {
-    if (status_ == kQuotaStatusUnknown)
-      status_ = kQuotaStatusOk;
-    usage_and_quota_.global_limited_usage = limited_usage;
-    CheckCompleted();
+  void SetDesiredHostQuota(const base::Closure& barrier_closure,
+                           QuotaStatusCode status,
+                           int64_t quota) {
+    desired_host_quota_ = quota;
+    barrier_closure.Run();
   }
 
-  void DidGetQuota(QuotaStatusCode status, int64_t quota) {
-    if (status_ == kQuotaStatusUnknown || status_ == kQuotaStatusOk)
-      status_ = status;
-    usage_and_quota_.quota = quota;
-    CheckCompleted();
-  }
+  void OnBarrierComplete() { CallCompleted(); }
 
-  void DidGetAvailableSpace(QuotaStatusCode status, int64_t space) {
-    // crbug.com/349708
-    TRACE_EVENT0(
-        "io", "UsageAndQuotaCallbackDispatcher::DidGetAvailableSpace");
+  GURL origin_;
+  QuotaManager::UsageAndQuotaCallback callback_;
+  StorageType type_;
+  bool is_unlimited_;
+  bool is_incognito_;
+  int64_t available_space_ = 0;
+  int64_t total_space_ = 0;
+  int64_t desired_host_quota_ = 0;
+  int64_t host_usage_ = 0;
+  QuotaSettings settings_;
+  base::WeakPtrFactory<UsageAndQuotaHelper> weak_factory_;
+  DISALLOW_COPY_AND_ASSIGN(UsageAndQuotaHelper);
+};
 
-    DCHECK_GE(space, 0);
-    if (status_ == kQuotaStatusUnknown || status_ == kQuotaStatusOk)
-      status_ = status;
-    usage_and_quota_.available_disk_space = space;
-    CheckCompleted();
-  }
+// Helper to asychronously gather information needed at the start of an
+// eviction round.
+class QuotaManager::EvictionRoundInfoHelper : public QuotaTask {
+ public:
+  EvictionRoundInfoHelper(QuotaManager* manager,
+                          const EvictionRoundInfoCallback& callback)
+      : QuotaTask(manager), callback_(callback), weak_factory_(this) {}
 
+ protected:
   void Run() override {
-    // We initialize waiting_callbacks to 1 so that we won't run
-    // the completion callback until here even some of the callbacks
-    // are dispatched synchronously.
-    CheckCompleted();
+    // Gather 2 pieces of info before deciding if we need to get GlobalUsage:
+    // settings and device_storage_capacity.
+    base::Closure barrier = base::BarrierClosure(
+        2, base::Bind(&EvictionRoundInfoHelper::OnBarrierComplete,
+                      weak_factory_.GetWeakPtr()));
+
+    manager()->GetQuotaSettings(
+        base::Bind(&EvictionRoundInfoHelper::OnGotSettings,
+                   weak_factory_.GetWeakPtr(), barrier));
+    manager()->GetStorageCapacity(
+        base::Bind(&EvictionRoundInfoHelper::OnGotCapacity,
+                   weak_factory_.GetWeakPtr(), barrier));
   }
 
   void Aborted() override {
-    callback_.Run(kQuotaErrorAbort, UsageAndQuota());
+    weak_factory_.InvalidateWeakPtrs();
+    callback_.Run(kQuotaErrorAbort, QuotaSettings(), 0, 0, 0, false);
     DeleteSoon();
   }
 
   void Completed() override {
-    // crbug.com/349708
-    TRACE_EVENT0("io", "UsageAndQuotaCallbackDispatcher::Completed");
-
-    DCHECK(!has_usage_ || usage_and_quota_.usage >= 0);
-    DCHECK(!has_global_limited_usage_ ||
-           usage_and_quota_.global_limited_usage >= 0);
-    DCHECK(!has_quota_ || usage_and_quota_.quota >= 0);
-    DCHECK(!has_available_disk_space_ ||
-           usage_and_quota_.available_disk_space >= 0);
-
-    callback_.Run(status_, usage_and_quota_);
+    weak_factory_.InvalidateWeakPtrs();
+    callback_.Run(kQuotaStatusOk, settings_, available_space_, total_space_,
+                  global_usage_, global_usage_is_complete_);
     DeleteSoon();
   }
 
-  void CheckCompleted() {
-    if (--waiting_callbacks_ <= 0)
-      CallCompleted();
+ private:
+  QuotaManager* manager() const {
+    return static_cast<QuotaManager*>(observer());
   }
 
-  // For sanity checks, they're checked only when DCHECK is on.
-  bool has_usage_;
-  bool has_global_limited_usage_;
-  bool has_quota_;
-  bool has_available_disk_space_;
+  void OnGotSettings(const base::Closure& barrier_closure,
+                     const QuotaSettings& settings) {
+    settings_ = settings;
+    barrier_closure.Run();
+  }
 
-  QuotaStatusCode status_;
-  UsageAndQuota usage_and_quota_;
-  QuotaManager::UsageAndQuotaCallback callback_;
-  int waiting_callbacks_;
+  void OnGotCapacity(const base::Closure& barrier_closure,
+                     int64_t total_space,
+                     int64_t available_space) {
+    total_space_ = total_space;
+    available_space_ = available_space;
+    barrier_closure.Run();
+  }
 
-  DISALLOW_COPY_AND_ASSIGN(UsageAndQuotaCallbackDispatcher);
+  void OnBarrierComplete() {
+    // Avoid computing the full current_usage when there's no pressure.
+    int64_t consumed_space = total_space_ - available_space_;
+    if (consumed_space < settings_.pool_size &&
+        available_space_ > settings_.must_remain_available) {
+      DCHECK(!global_usage_is_complete_);
+      global_usage_ =
+          manager()->GetUsageTracker(kStorageTypeTemporary)->GetCachedUsage();
+      CallCompleted();
+      return;
+    }
+    manager()->GetGlobalUsage(
+        kStorageTypeTemporary,
+        base::Bind(&EvictionRoundInfoHelper::OnGotGlobalUsage,
+                   weak_factory_.GetWeakPtr()));
+  }
+
+  void OnGotGlobalUsage(int64_t usage, int64_t unlimited_usage) {
+    global_usage_ = std::max(INT64_C(0), usage - unlimited_usage);
+    global_usage_is_complete_ = true;
+    CallCompleted();
+  }
+
+  EvictionRoundInfoCallback callback_;
+  QuotaSettings settings_;
+  int64_t available_space_ = 0;
+  int64_t total_space_ = 0;
+  int64_t global_usage_ = 0;
+  bool global_usage_is_complete_ = false;
+  base::WeakPtrFactory<EvictionRoundInfoHelper> weak_factory_;
+  DISALLOW_COPY_AND_ASSIGN(EvictionRoundInfoHelper);
 };
 
 class QuotaManager::GetUsageInfoTask : public QuotaTask {
@@ -866,7 +774,8 @@ QuotaManager::QuotaManager(
     const base::FilePath& profile_path,
     const scoped_refptr<base::SingleThreadTaskRunner>& io_thread,
     const scoped_refptr<base::SequencedTaskRunner>& db_thread,
-    const scoped_refptr<SpecialStoragePolicy>& special_storage_policy)
+    const scoped_refptr<SpecialStoragePolicy>& special_storage_policy,
+    const GetQuotaSettingsFunc& get_settings_function)
     : is_incognito_(is_incognito),
       profile_path_(profile_path),
       proxy_(new QuotaManagerProxy(this, io_thread)),
@@ -874,13 +783,25 @@ QuotaManager::QuotaManager(
       eviction_disabled_(false),
       io_thread_(io_thread),
       db_thread_(db_thread),
+      get_settings_function_(get_settings_function),
       is_getting_eviction_origin_(false),
-      temporary_quota_initialized_(false),
-      temporary_quota_override_(-1),
       special_storage_policy_(special_storage_policy),
       get_volume_info_fn_(&QuotaManager::GetVolumeInfo),
       storage_monitor_(new StorageMonitor(this)),
-      weak_factory_(this) {}
+      weak_factory_(this) {
+  DCHECK_EQ(settings_.refresh_interval, base::TimeDelta::Max());
+  if (!get_settings_function.is_null()) {
+    // Reset the interval to ensure we use the get_settings_function
+    // the first times settings_ is needed.
+    settings_.refresh_interval = base::TimeDelta();
+    get_settings_task_runner_ = base::ThreadTaskRunnerHandle::Get();
+  }
+}
+
+void QuotaManager::SetQuotaSettings(const QuotaSettings& settings) {
+  settings_ = settings;
+  settings_timestamp_ = base::TimeTicks::Now();
+}
 
 void QuotaManager::GetUsageInfo(const GetUsageInfoCallback& callback) {
   LazyInitialize();
@@ -888,64 +809,41 @@ void QuotaManager::GetUsageInfo(const GetUsageInfoCallback& callback) {
   get_usage_info->Start();
 }
 
+namespace {
+bool IsSupportedType(StorageType type) {
+  return type != kStorageTypeTemporary || type != kStorageTypePersistent ||
+         type != kStorageTypeSyncable;
+}
+
+bool IsSupportedIncognitoType(StorageType type) {
+  return type != kStorageTypeTemporary || type != kStorageTypePersistent;
+}
+}  // anon
+
 void QuotaManager::GetUsageAndQuotaForWebApps(
     const GURL& origin,
     StorageType type,
-    const GetUsageAndQuotaCallback& callback) {
-  // TODO(pkasting): Remove ScopedTracker below once crbug.com/477117 is fixed.
-  tracked_objects::ScopedTracker tracking_profile(
-      FROM_HERE_WITH_EXPLICIT_FUNCTION(
-          "477117 QuotaManager::GetUsageAndQuotaForWebApps"));
-  if (type != kStorageTypeTemporary &&
-      type != kStorageTypePersistent &&
-      type != kStorageTypeSyncable) {
+    const UsageAndQuotaCallback& callback) {
+  DCHECK(origin == origin.GetOrigin());
+  if (!IsSupportedType(type) ||
+      (is_incognito_ && !IsSupportedIncognitoType(type))) {
     callback.Run(kQuotaErrorNotSupported, 0, 0);
     return;
   }
-
-  DCHECK(origin == origin.GetOrigin());
   LazyInitialize();
-
-  bool unlimited = IsStorageUnlimited(origin, type);
-  bool can_query_disk_size = CanQueryDiskSize(origin);
-
-  UsageAndQuotaCallbackDispatcher* dispatcher =
-      new UsageAndQuotaCallbackDispatcher(this);
-
-  if (unlimited) {
-    dispatcher->set_quota(kNoLimit);
-  } else {
-    if (type == kStorageTypeTemporary) {
-      GetUsageTracker(type)->GetGlobalLimitedUsage(
-          dispatcher->GetGlobalLimitedUsageCallback());
-      GetTemporaryGlobalQuota(dispatcher->GetQuotaCallback());
-    } else if (type == kStorageTypePersistent) {
-      GetPersistentHostQuota(net::GetHostOrSpecFromURL(origin),
-                             dispatcher->GetQuotaCallback());
-    } else {
-      dispatcher->set_quota(kSyncableStorageDefaultHostQuota);
-    }
-  }
-
-  DCHECK(GetUsageTracker(type));
-  GetUsageTracker(type)->GetHostUsage(net::GetHostOrSpecFromURL(origin),
-                                      dispatcher->GetHostUsageCallback());
-
-  if (!is_incognito_ && (unlimited || can_query_disk_size))
-    GetAvailableSpace(dispatcher->GetAvailableSpaceCallback());
-
-  dispatcher->WaitForResults(base::Bind(
-      &DispatchUsageAndQuotaForWebApps,
-      type, is_incognito_, unlimited, can_query_disk_size,
-      callback));
+  UsageAndQuotaHelper* helper = new UsageAndQuotaHelper(
+      this, origin, type, IsStorageUnlimited(origin, type), is_incognito_,
+      callback);
+  helper->Start();
 }
 
-void QuotaManager::GetUsageAndQuota(
-    const GURL& origin, StorageType type,
-    const GetUsageAndQuotaCallback& callback) {
+void QuotaManager::GetUsageAndQuota(const GURL& origin,
+                                    StorageType type,
+                                    const UsageAndQuotaCallback& callback) {
   DCHECK(origin == origin.GetOrigin());
 
   if (IsStorageUnlimited(origin, type)) {
+    // TODO: This seems like a non-obvious odd behavior.
     callback.Run(kQuotaStatusOk, 0, kNoLimit);
     return;
   }
@@ -1008,7 +906,6 @@ void QuotaManager::DeleteHostData(const std::string& host,
                                   int quota_client_mask,
                                   const StatusCallback& callback) {
   LazyInitialize();
-
   if (host.empty() || clients_.empty()) {
     callback.Run(kQuotaStatusOk);
     return;
@@ -1019,72 +916,6 @@ void QuotaManager::DeleteHostData(const std::string& host,
   deleter->Start();
 }
 
-void QuotaManager::GetAvailableSpace(const AvailableSpaceCallback& callback) {
-  if (!available_space_callbacks_.Add(callback))
-    return;
-  // crbug.com/349708
-  TRACE_EVENT0("io", "QuotaManager::GetAvailableSpace");
-
-  PostTaskAndReplyWithResult(
-      db_thread_.get(),
-      FROM_HERE,
-      base::Bind(&QuotaManager::CallGetAmountOfFreeDiskSpace,
-                 get_volume_info_fn_, profile_path_),
-      base::Bind(&QuotaManager::DidGetAvailableSpace,
-                 weak_factory_.GetWeakPtr()));
-}
-
-void QuotaManager::GetTemporaryGlobalQuota(const QuotaCallback& callback) {
-  LazyInitialize();
-  if (!temporary_quota_initialized_) {
-    db_initialization_callbacks_.Add(base::Bind(
-        &QuotaManager::GetTemporaryGlobalQuota,
-        weak_factory_.GetWeakPtr(), callback));
-    return;
-  }
-
-  if (temporary_quota_override_ > 0) {
-    callback.Run(kQuotaStatusOk, temporary_quota_override_);
-    return;
-  }
-
-  UsageAndQuotaCallbackDispatcher* dispatcher =
-      new UsageAndQuotaCallbackDispatcher(this);
-  GetUsageTracker(kStorageTypeTemporary)->
-      GetGlobalLimitedUsage(dispatcher->GetGlobalLimitedUsageCallback());
-  GetAvailableSpace(dispatcher->GetAvailableSpaceCallback());
-  dispatcher->WaitForResults(
-      base::Bind(&DispatchTemporaryGlobalQuotaCallback, callback));
-}
-
-void QuotaManager::SetTemporaryGlobalOverrideQuota(
-    int64_t new_quota,
-    const QuotaCallback& callback) {
-  LazyInitialize();
-
-  if (new_quota < 0) {
-    if (!callback.is_null())
-      callback.Run(kQuotaErrorInvalidModification, -1);
-    return;
-  }
-
-  if (db_disabled_) {
-    if (!callback.is_null())
-      callback.Run(kQuotaErrorInvalidAccess, -1);
-    return;
-  }
-
-  int64_t* new_quota_ptr = new int64_t(new_quota);
-  PostTaskAndReplyWithResultForDBThread(
-      FROM_HERE,
-      base::Bind(&SetTemporaryGlobalOverrideQuotaOnDBThread,
-                 base::Unretained(new_quota_ptr)),
-      base::Bind(&QuotaManager::DidSetTemporaryGlobalOverrideQuota,
-                 weak_factory_.GetWeakPtr(),
-                 callback,
-                 base::Owned(new_quota_ptr)));
-}
-
 void QuotaManager::GetPersistentHostQuota(const std::string& host,
                                           const QuotaCallback& callback) {
   LazyInitialize();
@@ -1126,10 +957,8 @@ void QuotaManager::SetPersistentHostQuota(const std::string& host,
     return;
   }
 
-  if (kPerHostPersistentQuotaLimit < new_quota) {
-    // Cap the requested size at the per-host quota limit.
-    new_quota = kPerHostPersistentQuotaLimit;
-  }
+  // Cap the requested size at the per-host quota limit.
+  new_quota = std::min(new_quota, kPerHostPersistentQuotaLimit);
 
   if (db_disabled_) {
     callback.Run(kQuotaErrorInvalidAccess, -1);
@@ -1289,7 +1118,7 @@ QuotaManager::EvictionContext::~EvictionContext() {
 void QuotaManager::LazyInitialize() {
   DCHECK(io_thread_->BelongsToCurrentThread());
   if (database_) {
-    // Initialization seems to be done already.
+    // Already initialized.
     return;
   }
 
@@ -1307,17 +1136,45 @@ void QuotaManager::LazyInitialize() {
       clients_, kStorageTypeSyncable, special_storage_policy_.get(),
       storage_monitor_.get()));
 
-  int64_t* temporary_quota_override = new int64_t(-1);
-  int64_t* desired_available_space = new int64_t(-1);
+  if (!is_incognito_) {
+    histogram_timer_.Start(
+        FROM_HERE, base::TimeDelta::FromMilliseconds(kReportHistogramInterval),
+        this, &QuotaManager::ReportHistogram);
+  }
+
+  base::PostTaskAndReplyWithResult(
+      db_thread_.get(), FROM_HERE,
+      base::Bind(&QuotaDatabase::IsOriginDatabaseBootstrapped,
+                 base::Unretained(database_.get())),
+      base::Bind(&QuotaManager::FinishLazyInitialize,
+                 weak_factory_.GetWeakPtr()));
+}
+
+void QuotaManager::FinishLazyInitialize(bool is_database_bootstrapped) {
+  is_database_bootstrapped_ = is_database_bootstrapped;
+  StartEviction();
+}
+
+void QuotaManager::BootstrapDatabaseForEviction(
+    const GetOriginCallback& did_get_origin_callback,
+    int64_t usage,
+    int64_t unlimited_usage) {
+  // The usage cache should be fully populated now so we can
+  // seed the database with origins we know about.
+  std::set<GURL>* origins = new std::set<GURL>;
+  temporary_usage_tracker_->GetCachedOrigins(origins);
   PostTaskAndReplyWithResultForDBThread(
-      FROM_HERE,
-      base::Bind(&InitializeOnDBThread,
-                 base::Unretained(temporary_quota_override),
-                 base::Unretained(desired_available_space)),
-      base::Bind(&QuotaManager::DidInitialize,
-                 weak_factory_.GetWeakPtr(),
-                 base::Owned(temporary_quota_override),
-                 base::Owned(desired_available_space)));
+      FROM_HERE, base::Bind(&BootstrapDatabaseOnDBThread, base::Owned(origins)),
+      base::Bind(&QuotaManager::DidBootstrapDatabase,
+                 weak_factory_.GetWeakPtr(), did_get_origin_callback));
+}
+
+void QuotaManager::DidBootstrapDatabase(
+    const GetOriginCallback& did_get_origin_callback,
+    bool success) {
+  is_database_bootstrapped_ = success;
+  DidDatabaseWork(success);
+  GetLRUOrigin(kStorageTypeTemporary, did_get_origin_callback);
 }
 
 void QuotaManager::RegisterClient(QuotaClient* client) {
@@ -1412,11 +1269,10 @@ void QuotaManager::DumpOriginInfoTable(
 
 void QuotaManager::StartEviction() {
   DCHECK(!temporary_storage_evictor_.get());
+  if (eviction_disabled_)
+    return;
   temporary_storage_evictor_.reset(new QuotaTemporaryStorageEvictor(
       this, kEvictionIntervalInMilliSeconds));
-  if (desired_available_space_ >= 0)
-    temporary_storage_evictor_->set_min_available_disk_space_to_start_eviction(
-        desired_available_space_);
   temporary_storage_evictor_->Start();
 }
 
@@ -1602,6 +1458,7 @@ void QuotaManager::GetEvictionOrigin(StorageType type,
       base::Bind(&QuotaManager::DidGetEvictionOrigin,
                  weak_factory_.GetWeakPtr(), callback);
 
+  // TODO(michaeln): remove support for this for now?

[michaeln, 2016/11/11 02:36:28]

i think i'd like to to this as part of this CL? i'm not testing this codepath
and it's not currently used in the product (afaik). wdyt?

   if (type == kStorageTypeTemporary && temporary_storage_eviction_policy_) {
     std::map<GURL, int64_t> usage_map;
     // The cached origins are populated by the prior call to
@@ -1615,13 +1472,21 @@ void QuotaManager::GetEvictionOrigin(StorageType type,
     return;
   }
 
-  // TODO(calamity): convert LRU origin retrieval into a QuotaEvictionPolicy.
+  if (!is_database_bootstrapped_ && !eviction_disabled_) {
+    // Once bootstrapped, GetLRUOrigin will be called.
+    GetGlobalUsage(
+        kStorageTypeTemporary,
+        base::Bind(&QuotaManager::BootstrapDatabaseForEviction,
+                   weak_factory_.GetWeakPtr(), did_get_origin_callback));
+    return;
+  }
+
   GetLRUOrigin(type, did_get_origin_callback);
 }
 
 void QuotaManager::EvictOriginData(const GURL& origin,
                                    StorageType type,
-                                   const EvictOriginDataCallback& callback) {
+                                   const StatusCallback& callback) {
   DCHECK(io_thread_->BelongsToCurrentThread());
   DCHECK_EQ(type, kStorageTypeTemporary);
 
@@ -1634,47 +1499,12 @@ void QuotaManager::EvictOriginData(const GURL& origin,
                                       weak_factory_.GetWeakPtr()));
 }
 
-void QuotaManager::GetUsageAndQuotaForEviction(
-    const UsageAndQuotaCallback& callback) {
-  // crbug.com/349708
-  TRACE_EVENT0("io", "QuotaManager::GetUsageAndQuotaForEviction");
-
+void QuotaManager::GetEvictionRoundInfo(
+    const EvictionRoundInfoCallback& callback) {
   DCHECK(io_thread_->BelongsToCurrentThread());
   LazyInitialize();
-
-  UsageAndQuotaCallbackDispatcher* dispatcher =
-      new UsageAndQuotaCallbackDispatcher(this);
-  GetUsageTracker(kStorageTypeTemporary)
-      ->GetGlobalLimitedUsage(dispatcher->GetGlobalLimitedUsageCallback());
-  GetTemporaryGlobalQuota(dispatcher->GetQuotaCallback());
-  GetAvailableSpace(dispatcher->GetAvailableSpaceCallback());
-  dispatcher->WaitForResults(callback);
-}
-
-void QuotaManager::AsyncGetVolumeInfo(
-    const VolumeInfoCallback& callback) {
-  DCHECK(io_thread_->BelongsToCurrentThread());
-  uint64_t* available_space = new uint64_t(0);
-  uint64_t* total_space = new uint64_t(0);
-  PostTaskAndReplyWithResult(
-      db_thread_.get(),
-      FROM_HERE,
-      base::Bind(get_volume_info_fn_,
-                 profile_path_,
-                 base::Unretained(available_space),
-                 base::Unretained(total_space)),
-      base::Bind(&QuotaManager::DidGetVolumeInfo,
-                 weak_factory_.GetWeakPtr(),
-                 callback,
-                 base::Owned(available_space),
-                 base::Owned(total_space)));
-}
-
-void QuotaManager::DidGetVolumeInfo(
-    const VolumeInfoCallback& callback,
-    uint64_t* available_space, uint64_t* total_space, bool success) {
-  DCHECK(io_thread_->BelongsToCurrentThread());
-  callback.Run(success, *available_space, *total_space);
+  EvictionRoundInfoHelper* helper = new EvictionRoundInfoHelper(this, callback);
+  helper->Start();
 }
 
 void QuotaManager::GetLRUOrigin(StorageType type,
@@ -1699,28 +1529,12 @@ void QuotaManager::GetLRUOrigin(StorageType type,
                  base::Owned(url)));
 }
 
-void QuotaManager::DidSetTemporaryGlobalOverrideQuota(
-    const QuotaCallback& callback,
-    const int64_t* new_quota,
-    bool success) {
-  QuotaStatusCode status = kQuotaErrorInvalidAccess;
-  DidDatabaseWork(success);
-  if (success) {
-    temporary_quota_override_ = *new_quota;
-    status = kQuotaStatusOk;
-  }
-
-  if (callback.is_null())
-    return;
-
-  callback.Run(status, *new_quota);
-}
-
 void QuotaManager::DidGetPersistentHostQuota(const std::string& host,
                                              const int64_t* quota,
                                              bool success) {
   DidDatabaseWork(success);
-  persistent_host_quota_callbacks_.Run(host, kQuotaStatusOk, *quota);
+  persistent_host_quota_callbacks_.Run(
+      host, kQuotaStatusOk, std::min(*quota, kPerHostPersistentQuotaLimit));
 }
 
 void QuotaManager::DidSetPersistentHostQuota(const std::string& host,
@@ -1731,27 +1545,6 @@ void QuotaManager::DidSetPersistentHostQuota(const std::string& host,
   callback.Run(success ? kQuotaStatusOk : kQuotaErrorInvalidAccess, *new_quota);
 }
 
-void QuotaManager::DidInitialize(int64_t* temporary_quota_override,
-                                 int64_t* desired_available_space,
-                                 bool success) {
-  temporary_quota_override_ = *temporary_quota_override;
-  desired_available_space_ = *desired_available_space;
-  temporary_quota_initialized_ = true;
-  DidDatabaseWork(success);
-
-  if (!is_incognito_) {
-    histogram_timer_.Start(FROM_HERE,
-                           base::TimeDelta::FromMilliseconds(
-                               kReportHistogramInterval),
-                           this, &QuotaManager::ReportHistogram);
-  }
-
-  db_initialization_callbacks_.Run();
-  GetTemporaryGlobalQuota(
-      base::Bind(&QuotaManager::DidGetInitialTemporaryGlobalQuota,
-                 weak_factory_.GetWeakPtr(), base::TimeTicks::Now()));
-}
-
 void QuotaManager::DidGetLRUOrigin(const GURL* origin,
                                    bool success) {
   DidDatabaseWork(success);
@@ -1760,41 +1553,81 @@ void QuotaManager::DidGetLRUOrigin(const GURL* origin,
   lru_origin_callback_.Reset();
 }
 
-void QuotaManager::DidGetInitialTemporaryGlobalQuota(
-    base::TimeTicks start_ticks,
-    QuotaStatusCode status,
-    int64_t quota_unused) {
-  UMA_HISTOGRAM_LONG_TIMES(
-      "Quota.TimeToInitializeGlobalQuota",
-      base::TimeTicks::Now() - start_ticks);
+namespace {
+void DidGetSettingsThreadAdapter(base::TaskRunner* task_runner,
+                                 const OptionalQuotaSettingsCallback& callback,
+                                 base::Optional<QuotaSettings> settings) {
+  task_runner->PostTask(FROM_HERE, base::Bind(callback, std::move(settings)));
+}
+}  // namespace
 
-  if (eviction_disabled_)
+void QuotaManager::GetQuotaSettings(const QuotaSettingsCallback& callback) {
+  if (base::TimeTicks::Now() - settings_timestamp_ <
+      settings_.refresh_interval) {
+    callback.Run(settings_);
     return;
+  }
 
-  std::set<GURL>* origins = new std::set<GURL>;
-  temporary_usage_tracker_->GetCachedOrigins(origins);
-  // This will call the StartEviction() when initial origin registration
-  // is completed.
-  PostTaskAndReplyWithResultForDBThread(
+  if (!settings_callbacks_.Add(callback))
+    return;
+
+  // We invoke our clients GetQuotaSettingsFunc on the
+  // UI thread and plumb the resulting value back to this thread.
+  get_settings_task_runner_->PostTask(
       FROM_HERE,
-      base::Bind(&InitializeTemporaryOriginsInfoOnDBThread,
-                 base::Owned(origins)),
-      base::Bind(&QuotaManager::DidInitializeTemporaryOriginsInfo,
+      base::Bind(
+          get_settings_function_, profile_path_, is_incognito_,
+          base::Bind(&DidGetSettingsThreadAdapter,
+                     base::RetainedRef(base::ThreadTaskRunnerHandle::Get()),
+                     base::Bind(&QuotaManager::DidGetSettings,
+                                weak_factory_.GetWeakPtr(),
+                                base::TimeTicks::Now()))));
+}
+
+void QuotaManager::DidGetSettings(base::TimeTicks start_ticks,
+                                  base::Optional<QuotaSettings> settings) {
+  if (!settings) {
+    settings = settings_;
+    settings->refresh_interval = base::TimeDelta::FromMinutes(1);
+  }
+  SetQuotaSettings(*settings);
+  settings_callbacks_.Run(*settings);
+  UMA_HISTOGRAM_MBYTES("Quota.GlobalTemporaryPoolSize", settings->pool_size);
+  UMA_HISTOGRAM_LONG_TIMES("Quota.TimeToGetSettings",
+                           base::TimeTicks::Now() - start_ticks);
+}
+
+void QuotaManager::GetStorageCapacity(const StorageCapacityCallback& callback) {
+  if (!storage_capacity_callbacks_.Add(callback))
+    return;
+  if (is_incognito_) {
+    GetQuotaSettings(
+        base::Bind(&QuotaManager::ContinueIncognitoGetStorageCapacity,
+                   weak_factory_.GetWeakPtr()));
+    return;
+  }
+  base::PostTaskAndReplyWithResult(
+      db_thread_.get(), FROM_HERE,
+      base::Bind(&QuotaManager::CallGetVolumeInfo, get_volume_info_fn_,
+                 profile_path_),
+      base::Bind(&QuotaManager::DidGetStorageCapacity,
                  weak_factory_.GetWeakPtr()));
 }
 
-void QuotaManager::DidInitializeTemporaryOriginsInfo(bool success) {
-  DidDatabaseWork(success);
-  if (success)
-    StartEviction();
+void QuotaManager::ContinueIncognitoGetStorageCapacity(
+    const QuotaSettings& settings) {
+  int64_t current_usage =
+      GetUsageTracker(kStorageTypeTemporary)->GetCachedUsage();
+  current_usage += GetUsageTracker(kStorageTypePersistent)->GetCachedUsage();
+  int64_t available_space =
+      std::max(INT64_C(0), settings.pool_size - current_usage);
+  DidGetStorageCapacity(std::make_pair(settings.pool_size, available_space));
 }
 
-void QuotaManager::DidGetAvailableSpace(int64_t space) {
-  // crbug.com/349708
-  TRACE_EVENT1("io", "QuotaManager::DidGetAvailableSpace",
-               "n_callbacks", available_space_callbacks_.size());
-
-  available_space_callbacks_.Run(kQuotaStatusOk, space);
+void QuotaManager::DidGetStorageCapacity(
+    const std::pair<int64_t, int64_t>& total_and_available) {
+  storage_capacity_callbacks_.Run(total_and_available.first,
+                                  total_and_available.second);
 }
 
 void QuotaManager::DidDatabaseWork(bool success) {
@@ -1824,41 +1657,30 @@ void QuotaManager::PostTaskAndReplyWithResultForDBThread(
 }
 
 // static
-int64_t QuotaManager::CallGetAmountOfFreeDiskSpace(
+std::pair<int64_t, int64_t> QuotaManager::CallGetVolumeInfo(
     GetVolumeInfoFn get_volume_info_fn,
-    const base::FilePath& profile_path) {
+    const base::FilePath& path) {
   // crbug.com/349708
-  TRACE_EVENT0("io", "CallSystemGetAmountOfFreeDiskSpace");
-  if (!base::CreateDirectory(profile_path)) {
-    LOG(WARNING) << "Create directory failed for path" << profile_path.value();
-    return 0;
+  TRACE_EVENT0("io", "CallGetVolumeInfo");
+  if (!base::CreateDirectory(path)) {
+    LOG(WARNING) << "Create directory failed for path" << path.value();
+    return std::make_pair<int64_t, int64_t>(0, 0);
   }
-  uint64_t available, total;
-  if (!get_volume_info_fn(profile_path, &available, &total)) {
-    return 0;
+  std::pair<int64_t, int64_t> total_and_available = get_volume_info_fn(path);
+  if (total_and_available.first < 0 || total_and_available.second < 0) {
+    LOG(WARNING) << "Unable to get volume info: " << path.value();
+    return std::make_pair<int64_t, int64_t>(0, 0);
   }
-  UMA_HISTOGRAM_MBYTES("Quota.AvailableDiskSpace", available);
-  UMA_HISTOGRAM_MBYTES("Quota.TotalDiskSpace", total);
-  return static_cast<int64_t>(available);
+  UMA_HISTOGRAM_MBYTES("Quota.TotalDiskSpace", total_and_available.first);
+  UMA_HISTOGRAM_MBYTES("Quota.AvailableDiskSpace", total_and_available.second);
+  return total_and_available;
 }
 
-//static
-bool QuotaManager::GetVolumeInfo(const base::FilePath& path,
-                                 uint64_t* available_space,
-                                 uint64_t* total_size) {
-  // Inspired by similar code in the base::SysInfo class.
-  base::ThreadRestrictions::AssertIOAllowed();
-
-  int64_t available = base::SysInfo::AmountOfFreeDiskSpace(path);
-  if (available < 0)
-    return false;
-  int64_t total = base::SysInfo::AmountOfTotalDiskSpace(path);
-  if (total < 0)
-    return false;
-
-  *available_space = static_cast<uint64_t>(available);
-  *total_size = static_cast<uint64_t>(total);
-  return true;
+// static
+std::pair<int64_t, int64_t> QuotaManager::GetVolumeInfo(
+    const base::FilePath& path) {
+  return std::make_pair(base::SysInfo::AmountOfTotalDiskSpace(path),
+                        base::SysInfo::AmountOfFreeDiskSpace(path));
 }
 
 }  // namespace storage