[GCM] Adding GCMAccountMapper to link signed in profile to accounts.

* Addes GCMAccountMapper with tests for adding and removing accoounts.

BUG=374969

Review URL: https://codereview.chromium.org/491443004

Cr-Commit-Position: refs/heads/master@{#293308}

6 files changed, 1017 insertions, 1 deletions

diff --git a/components/components_tests.gyp b/components/components_tests.gyp
index 37f3fc8..f1e0663 100644
--- a/components/components_tests.gyp
+++ b/components/components_tests.gyp
@@ -119,6 +119,7 @@
             'feedback/feedback_common_unittest.cc',
             'feedback/feedback_data_unittest.cc',
             'feedback/feedback_uploader_unittest.cc',
+            'gcm_driver/gcm_account_mapper_unittest.cc',
             'gcm_driver/gcm_client_impl_unittest.cc',
             'gcm_driver/gcm_driver_desktop_unittest.cc',
             'gcm_driver/gcm_stats_recorder_impl_unittest.cc',
@@ -439,7 +440,7 @@
                 'components.gyp:autofill_content_browser',
                 'components.gyp:autofill_content_renderer',
                 'components.gyp:autofill_content_test_support',
-                
+
                 # Dependencies of component_updater
                 'components.gyp:component_updater',
                 'components.gyp:component_updater_test_support',
@@ -577,6 +578,7 @@
             }],
             ['OS == "android"', {
               'sources!': [
+                'gcm_driver/gcm_account_mapper_unittest.cc',
                 'gcm_driver/gcm_client_impl_unittest.cc',
                 'gcm_driver/gcm_driver_desktop_unittest.cc',
                 'feedback/feedback_common_unittest.cc',
diff --git a/components/gcm_driver.gypi b/components/gcm_driver.gypi
index b9336e5..7efe3c0 100644
--- a/components/gcm_driver.gypi
+++ b/components/gcm_driver.gypi
@@ -23,6 +23,8 @@
         'gcm_driver/android/component_jni_registrar.h',
         'gcm_driver/default_gcm_app_handler.cc',
         'gcm_driver/default_gcm_app_handler.h',
+        'gcm_driver/gcm_account_mapper.cc',
+        'gcm_driver/gcm_account_mapper.h',
         'gcm_driver/gcm_activity.cc',
         'gcm_driver/gcm_activity.h',
         'gcm_driver/gcm_app_handler.cc',
@@ -55,6 +57,8 @@
             '../google_apis/gcm/gcm.gyp:gcm',
           ],
           'sources!': [
+            'gcm_driver/gcm_account_mapper.cc',
+            'gcm_driver/gcm_account_mapper.h',
             'gcm_driver/gcm_client_factory.cc',
             'gcm_driver/gcm_client_factory.h',
             'gcm_driver/gcm_client_impl.cc',
diff --git a/components/gcm_driver/gcm_account_mapper.cc b/components/gcm_driver/gcm_account_mapper.cc
new file mode 100644
index 0000000..0e54fd5
--- /dev/null
+++ b/components/gcm_driver/gcm_account_mapper.cc
@@ -0,0 +1,327 @@
+// Copyright 2014 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 "components/gcm_driver/gcm_account_mapper.h"
+
+#include "base/bind.h"
+#include "base/guid.h"
+#include "base/time/clock.h"
+#include "base/time/default_clock.h"
+#include "components/gcm_driver/gcm_driver_desktop.h"
+#include "google_apis/gcm/engine/gcm_store.h"
+
+namespace gcm {
+
+namespace {
+
+const char kGCMAccountMapperSenderId[] = "745476177629";
+const char kGCMAccountMapperAppId[] = "com.google.android.gms";
+const int kGCMAddMappingMessageTTL = 30 * 60;  // 0.5 hours in seconds.
+const int kGCMRemoveMappingMessageTTL = 24 * 60 * 60;  // 1 day in seconds.
+const int kGCMUpdateIntervalHours = 24;
+// Because adding an account mapping dependents on a fresh OAuth2 token, we
+// allow the update to happen earlier than update due time, if it is within
+// the early start time to take advantage of that token.
+const int kGCMUpdateEarlyStartHours = 6;
+const char kRegistrationIdMessgaeKey[] = "id";
+const char kTokenMessageKey[] = "t";
+const char kAccountMessageKey[] = "a";
+const char kRemoveAccountKey[] = "r";
+const char kRemoveAccountValue[] = "1";
+
+std::string GenerateMessageID() {
+  return base::GenerateGUID();
+}
+
+}  // namespace
+
+GCMAccountMapper::GCMAccountMapper(GCMDriver* gcm_driver)
+    : gcm_driver_(gcm_driver),
+      clock_(new base::DefaultClock),
+      initialized_(false),
+      weak_ptr_factory_(this) {
+}
+
+GCMAccountMapper::~GCMAccountMapper() {
+}
+
+void GCMAccountMapper::Initialize(
+    const std::vector<AccountMapping>& account_mappings,
+    const std::string& registration_id) {
+  DCHECK(!initialized_);
+  initialized_ = true;
+  registration_id_ = registration_id;
+
+  accounts_ = account_mappings;
+
+  gcm_driver_->AddAppHandler(kGCMAccountMapperAppId, this);
+
+  // TODO(fgorski): if no registration ID, get registration ID.
+}
+
+void GCMAccountMapper::SetAccountTokens(
+    const std::vector<GCMClient::AccountTokenInfo> account_tokens) {
+  DCHECK(initialized_);
+
+  // Start from removing the old tokens, from all of the known accounts.
+  for (AccountMappings::iterator iter = accounts_.begin();
+       iter != accounts_.end();
+       ++iter) {
+    iter->access_token.clear();
+  }
+
+  // Update the internal collection of mappings with the new tokens.
+  for (std::vector<GCMClient::AccountTokenInfo>::const_iterator token_iter =
+           account_tokens.begin();
+       token_iter != account_tokens.end();
+       ++token_iter) {
+    AccountMapping* account_mapping =
+        FindMappingByAccountId(token_iter->account_id);
+    if (!account_mapping) {
+      AccountMapping new_mapping;
+      new_mapping.status = AccountMapping::NEW;
+      new_mapping.account_id = token_iter->account_id;
+      new_mapping.access_token = token_iter->access_token;
+      new_mapping.email = token_iter->email;
+      accounts_.push_back(new_mapping);
+    } else {
+      // Since we got a token for an account, drop the remove message and treat
+      // it as mapped.
+      if (account_mapping->status == AccountMapping::REMOVING) {
+        account_mapping->status = AccountMapping::MAPPED;
+        account_mapping->status_change_timestamp = base::Time();
+        account_mapping->last_message_id.clear();
+      }
+
+      account_mapping->email = token_iter->email;
+      account_mapping->access_token = token_iter->access_token;
+    }
+  }
+
+  // Decide what to do with each account (either start mapping, or start
+  // removing).
+  for (AccountMappings::iterator mappings_iter = accounts_.begin();
+       mappings_iter != accounts_.end();
+       ++mappings_iter) {
+    if (mappings_iter->access_token.empty()) {
+      // Send a remove message if the account was not previously being removed,
+      // or it doesn't have a pending message, or the pending message is
+      // already expired, but OnSendError event was lost.
+      if (mappings_iter->status != AccountMapping::REMOVING ||
+          mappings_iter->last_message_id.empty() ||
+          IsLastStatusChangeOlderThanTTL(*mappings_iter)) {
+        SendRemoveMappingMessage(*mappings_iter);
+      }
+    } else {
+      // A message is sent for all of the mappings considered NEW, or mappings
+      // that are ADDING, but have expired message (OnSendError event lost), or
+      // for those mapped accounts that can be refreshed.
+      if (mappings_iter->status == AccountMapping::NEW ||
+          (mappings_iter->status == AccountMapping::ADDING &&
+           IsLastStatusChangeOlderThanTTL(*mappings_iter)) ||
+          (mappings_iter->status == AccountMapping::MAPPED &&
+           CanTriggerUpdate(mappings_iter->status_change_timestamp))) {
+        mappings_iter->last_message_id.clear();
+        SendAddMappingMessage(*mappings_iter);
+      }
+    }
+  }
+}
+
+void GCMAccountMapper::ShutdownHandler() {
+  gcm_driver_->RemoveAppHandler(kGCMAccountMapperAppId);
+}
+
+void GCMAccountMapper::OnMessage(const std::string& app_id,
+                                 const GCMClient::IncomingMessage& message) {
+  // Account message does not expect messages right now.
+}
+
+void GCMAccountMapper::OnMessagesDeleted(const std::string& app_id) {
+  // Account message does not expect messages right now.
+}
+
+void GCMAccountMapper::OnSendError(
+    const std::string& app_id,
+    const GCMClient::SendErrorDetails& send_error_details) {
+  DCHECK_EQ(app_id, kGCMAccountMapperAppId);
+
+  AccountMappings::iterator account_mapping_it =
+      FindMappingByMessageId(send_error_details.message_id);
+
+  if (account_mapping_it == accounts_.end())
+    return;
+
+  if (send_error_details.result != GCMClient::TTL_EXCEEDED) {
+    DVLOG(1) << "Send error result different than TTL EXCEEDED: "
+             << send_error_details.result << ". "
+             << "Postponing the retry until a new batch of tokens arrives.";
+    return;
+  }
+
+  if (account_mapping_it->status == AccountMapping::REMOVING) {
+    // Another message to remove mapping can be sent immediately, because TTL
+    // for those is one day. No need to back off.
+    SendRemoveMappingMessage(*account_mapping_it);
+  } else {
+    if (account_mapping_it->status == AccountMapping::ADDING) {
+      // There is no mapping established, so we can remove the entry.
+      // Getting a fresh token will trigger a new attempt.
+      gcm_driver_->RemoveAccountMapping(account_mapping_it->account_id);
+      accounts_.erase(account_mapping_it);
+    } else {
+      // Account is already MAPPED, we have to wait for another token.
+      account_mapping_it->last_message_id.clear();
+      gcm_driver_->UpdateAccountMapping(*account_mapping_it);
+    }
+  }
+}
+
+void GCMAccountMapper::OnSendAcknowledged(const std::string& app_id,
+                                          const std::string& message_id) {
+  DCHECK_EQ(app_id, kGCMAccountMapperAppId);
+  AccountMappings::iterator account_mapping_it =
+      FindMappingByMessageId(message_id);
+
+  DVLOG(1) << "OnSendAcknowledged with message ID: " << message_id;
+
+  if (account_mapping_it == accounts_.end())
+    return;
+
+  // Here is where we advance a status of a mapping and persist or remove.
+  if (account_mapping_it->status == AccountMapping::REMOVING) {
+    // Message removing the account has been confirmed by the GCM, we can remove
+    // all the information related to the account (from memory and store).
+    gcm_driver_->RemoveAccountMapping(account_mapping_it->account_id);
+    accounts_.erase(account_mapping_it);
+  } else {
+    // Mapping status is ADDING only when it is a first time mapping.
+    DCHECK(account_mapping_it->status == AccountMapping::ADDING ||
+           account_mapping_it->status == AccountMapping::MAPPED);
+
+    // Account is marked as mapped with the current time.
+    account_mapping_it->status = AccountMapping::MAPPED;
+    account_mapping_it->status_change_timestamp = clock_->Now();
+    // There is no pending message for the account.
+    account_mapping_it->last_message_id.clear();
+
+    gcm_driver_->UpdateAccountMapping(*account_mapping_it);
+  }
+}
+
+bool GCMAccountMapper::CanHandle(const std::string& app_id) const {
+  return app_id.compare(kGCMAccountMapperAppId) == 0;
+}
+
+void GCMAccountMapper::SendAddMappingMessage(AccountMapping& account_mapping) {
+  CreateAndSendMessage(account_mapping);
+}
+
+void GCMAccountMapper::SendRemoveMappingMessage(
+    AccountMapping& account_mapping) {
+  // We want to persist an account that is being removed as quickly as possible
+  // as well as clean up the last message information.
+  if (account_mapping.status != AccountMapping::REMOVING) {
+    account_mapping.status = AccountMapping::REMOVING;
+    account_mapping.status_change_timestamp = clock_->Now();
+  }
+
+  account_mapping.last_message_id.clear();
+
+  gcm_driver_->UpdateAccountMapping(account_mapping);
+
+  CreateAndSendMessage(account_mapping);
+}
+
+void GCMAccountMapper::CreateAndSendMessage(
+    const AccountMapping& account_mapping) {
+  GCMClient::OutgoingMessage outgoing_message;
+  outgoing_message.id = GenerateMessageID();
+  outgoing_message.data[kRegistrationIdMessgaeKey] = registration_id_;
+  outgoing_message.data[kAccountMessageKey] = account_mapping.email;
+
+  if (account_mapping.status == AccountMapping::REMOVING) {
+    outgoing_message.time_to_live = kGCMRemoveMappingMessageTTL;
+    outgoing_message.data[kRemoveAccountKey] = kRemoveAccountValue;
+  } else {
+    outgoing_message.data[kTokenMessageKey] = account_mapping.access_token;
+    outgoing_message.time_to_live = kGCMAddMappingMessageTTL;
+  }
+
+  gcm_driver_->Send(kGCMAccountMapperAppId,
+                    kGCMAccountMapperSenderId,
+                    outgoing_message,
+                    base::Bind(&GCMAccountMapper::OnSendFinished,
+                               weak_ptr_factory_.GetWeakPtr(),
+                               account_mapping.account_id));
+}
+
+
+void GCMAccountMapper::OnSendFinished(const std::string& account_id,
+                                      const std::string& message_id,
+                                      GCMClient::Result result) {
+  // TODO(fgorski): Add another attempt, in case the QUEUE is not full.
+  if (result != GCMClient::SUCCESS)
+    return;
+
+  AccountMapping* account_mapping = FindMappingByAccountId(account_id);
+  DCHECK(account_mapping);
+
+  // If we are dealing with account with status NEW, it is the first time
+  // mapping, and we should mark it as ADDING.
+  if (account_mapping->status == AccountMapping::NEW) {
+    account_mapping->status = AccountMapping::ADDING;
+    account_mapping->status_change_timestamp = clock_->Now();
+  }
+
+  account_mapping->last_message_id = message_id;
+
+  gcm_driver_->UpdateAccountMapping(*account_mapping);
+}
+
+bool GCMAccountMapper::CanTriggerUpdate(
+    const base::Time& last_update_time) const {
+  return last_update_time +
+             base::TimeDelta::FromHours(kGCMUpdateIntervalHours -
+                                        kGCMUpdateEarlyStartHours) <
+         clock_->Now();
+}
+
+bool GCMAccountMapper::IsLastStatusChangeOlderThanTTL(
+    const AccountMapping& account_mapping) const {
+  int ttl_seconds = account_mapping.status == AccountMapping::REMOVING ?
+      kGCMRemoveMappingMessageTTL : kGCMAddMappingMessageTTL;
+  return account_mapping.status_change_timestamp +
+      base::TimeDelta::FromSeconds(ttl_seconds) < clock_->Now();
+}
+
+AccountMapping* GCMAccountMapper::FindMappingByAccountId(
+    const std::string& account_id) {
+  for (AccountMappings::iterator iter = accounts_.begin();
+       iter != accounts_.end();
+       ++iter) {
+    if (iter->account_id == account_id)
+      return &*iter;
+  }
+
+  return NULL;
+}
+
+GCMAccountMapper::AccountMappings::iterator
+GCMAccountMapper::FindMappingByMessageId(const std::string& message_id) {
+  for (std::vector<AccountMapping>::iterator iter = accounts_.begin();
+       iter != accounts_.end();
+       ++iter) {
+    if (iter->last_message_id == message_id)
+      return iter;
+  }
+
+  return accounts_.end();
+}
+
+void GCMAccountMapper::SetClockForTesting(scoped_ptr<base::Clock> clock) {
+  clock_ = clock.Pass();
+}
+
+}  // namespace gcm
diff --git a/components/gcm_driver/gcm_account_mapper.h b/components/gcm_driver/gcm_account_mapper.h
new file mode 100644
index 0000000..43d3365
--- /dev/null
+++ b/components/gcm_driver/gcm_account_mapper.h
@@ -0,0 +1,113 @@
+// Copyright 2014 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.
+
+#ifndef COMPONENTS_GCM_DRIVER_GCM_ACCOUNT_MAPPER_H_
+#define COMPONENTS_GCM_DRIVER_GCM_ACCOUNT_MAPPER_H_
+
+#include <string>
+#include <vector>
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "components/gcm_driver/gcm_app_handler.h"
+#include "components/gcm_driver/gcm_client.h"
+#include "google_apis/gcm/engine/account_mapping.h"
+
+namespace base {
+class Clock;
+}
+
+namespace gcm {
+
+class GCMDriver;
+
+// Class for mapping signed-in GAIA accounts to the GCM Device ID.
+class GCMAccountMapper : public GCMAppHandler {
+ public:
+  // List of account mappings.
+  typedef std::vector<AccountMapping> AccountMappings;
+
+  explicit GCMAccountMapper(GCMDriver* gcm_driver);
+  virtual ~GCMAccountMapper();
+
+  void Initialize(const AccountMappings& account_mappings,
+                  const std::string& registration_id);
+
+  // Called by AccountTracker, when a new list of account tokens is available.
+  // This will cause a refresh of account mappings and sending updates to GCM.
+  void SetAccountTokens(
+      const std::vector<GCMClient::AccountTokenInfo> account_tokens);
+
+  // Implementation of GCMAppHandler:
+  virtual void ShutdownHandler() OVERRIDE;
+  virtual void OnMessage(const std::string& app_id,
+                         const GCMClient::IncomingMessage& message) OVERRIDE;
+  virtual void OnMessagesDeleted(const std::string& app_id) OVERRIDE;
+  virtual void OnSendError(
+      const std::string& app_id,
+      const GCMClient::SendErrorDetails& send_error_details) OVERRIDE;
+  virtual void OnSendAcknowledged(const std::string& app_id,
+                                  const std::string& message_id) OVERRIDE;
+  virtual bool CanHandle(const std::string& app_id) const OVERRIDE;
+
+ private:
+  friend class GCMAccountMapperTest;
+
+  typedef std::map<std::string, GCMClient::OutgoingMessage> OutgoingMessages;
+
+  // Informs GCM of an added or refreshed account mapping.
+  void SendAddMappingMessage(AccountMapping& account_mapping);
+
+  // Informs GCM of a removed account mapping.
+  void SendRemoveMappingMessage(AccountMapping& account_mapping);
+
+  void CreateAndSendMessage(const AccountMapping& account_mapping);
+
+  // Callback for sending a message.
+  void OnSendFinished(const std::string& account_id,
+                      const std::string& message_id,
+                      GCMClient::Result result);
+
+  // Checks whether the update can be triggered now. If the current time is
+  // within reasonable time (6 hours) of when the update is due, we want to
+  // trigger the update immediately to take advantage of a fresh OAuth2 token.
+  bool CanTriggerUpdate(const base::Time& last_update_time) const;
+
+  // Checks whether last status change is older than a TTL of a message.
+  bool IsLastStatusChangeOlderThanTTL(
+      const AccountMapping& account_mapping) const;
+
+  // Finds an account mapping in |accounts_| by |account_id|.
+  AccountMapping* FindMappingByAccountId(const std::string& account_id);
+  // Finds an account mapping in |accounts_| by |message_id|.
+  // Returns iterator that can be used to delete the account.
+  AccountMappings::iterator FindMappingByMessageId(
+      const std::string& message_id);
+
+  // Sets the clock for testing.
+  void SetClockForTesting(scoped_ptr<base::Clock> clock);
+
+  // GCMDriver owns GCMAccountMapper.
+  GCMDriver* gcm_driver_;
+
+  // Clock for timestamping status changes.
+  scoped_ptr<base::Clock> clock_;
+
+  // Currnetly tracked account mappings.
+  AccountMappings accounts_;
+
+  // GCM Registration ID of the account mapper.
+  std::string registration_id_;
+
+  bool initialized_;
+
+  base::WeakPtrFactory<GCMAccountMapper> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(GCMAccountMapper);
+};
+
+}  // namespace gcm
+
+#endif  // COMPONENTS_GCM_DRIVER_GCM_ACCOUNT_MAPPER_H_
diff --git a/components/gcm_driver/gcm_account_mapper_unittest.cc b/components/gcm_driver/gcm_account_mapper_unittest.cc
new file mode 100644
index 0000000..b1983e6
--- /dev/null
+++ b/components/gcm_driver/gcm_account_mapper_unittest.cc
@@ -0,0 +1,563 @@
+// Copyright 2014 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 "components/gcm_driver/gcm_account_mapper.h"
+
+#include "base/test/simple_test_clock.h"
+#include "base/time/time.h"
+#include "components/gcm_driver/fake_gcm_driver.h"
+#include "google_apis/gcm/engine/account_mapping.h"
+#include "google_apis/gcm/engine/gcm_store.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace gcm {
+
+namespace {
+
+const char kGCMAccountMapperSenderId[] = "745476177629";
+const char kGCMAccountMapperAppId[] = "com.google.android.gms";
+const char kRegistrationId[] = "reg_id";
+
+AccountMapping MakeAccountMapping(const std::string& account_id,
+                                  AccountMapping::MappingStatus status,
+                                  const base::Time& status_change_timestamp,
+                                  const std::string& last_message_id) {
+  AccountMapping account_mapping;
+  account_mapping.account_id = account_id;
+  account_mapping.email = account_id + "@gmail.com";
+  // account_mapping.access_token intentionally left empty.
+  account_mapping.status = status;
+  account_mapping.status_change_timestamp = status_change_timestamp;
+  account_mapping.last_message_id = last_message_id;
+  return account_mapping;
+}
+
+GCMClient::AccountTokenInfo MakeAccountTokenInfo(
+    const std::string& account_id) {
+  GCMClient::AccountTokenInfo account_token;
+  account_token.account_id = account_id;
+  account_token.email = account_id + "@gmail.com";
+  account_token.access_token = account_id + "_token";
+  return account_token;
+}
+
+class CustomFakeGCMDriver : public FakeGCMDriver {
+ public:
+  CustomFakeGCMDriver();
+  virtual ~CustomFakeGCMDriver();
+
+  virtual void UpdateAccountMapping(
+      const AccountMapping& account_mapping) OVERRIDE;
+  virtual void RemoveAccountMapping(const std::string& account_id) OVERRIDE;
+  virtual void AddAppHandler(const std::string& app_id,
+                             GCMAppHandler* handler) OVERRIDE;
+  virtual void RemoveAppHandler(const std::string& app_id) OVERRIDE;
+
+  void CompleteSend(const std::string& message_id, GCMClient::Result result);
+  void SendAcknowledged(const std::string& message_id);
+  void MessageSendError(const std::string& message_id);
+
+  const AccountMapping& last_account_mapping() const {
+    return account_mapping_;
+  }
+  const std::string& last_message_id() const { return last_message_id_; }
+  const std::string& last_removed_account_id() const {
+    return last_removed_account_id_;
+  }
+
+ protected:
+  virtual void SendImpl(const std::string& app_id,
+                        const std::string& receiver_id,
+                        const GCMClient::OutgoingMessage& message) OVERRIDE;
+
+ private:
+  AccountMapping account_mapping_;
+  std::string last_message_id_;
+  std::string last_removed_account_id_;
+};
+
+CustomFakeGCMDriver::CustomFakeGCMDriver() {
+}
+
+CustomFakeGCMDriver::~CustomFakeGCMDriver() {
+}
+
+void CustomFakeGCMDriver::UpdateAccountMapping(
+    const AccountMapping& account_mapping) {
+  account_mapping_.email = account_mapping.email;
+  account_mapping_.account_id = account_mapping.account_id;
+  account_mapping_.access_token = account_mapping.access_token;
+  account_mapping_.status = account_mapping.status;
+  account_mapping_.status_change_timestamp =
+      account_mapping.status_change_timestamp;
+  account_mapping_.last_message_id = account_mapping.last_message_id;
+}
+
+void CustomFakeGCMDriver::RemoveAccountMapping(const std::string& account_id) {
+  last_removed_account_id_ = account_id;
+}
+
+void CustomFakeGCMDriver::AddAppHandler(const std::string& app_id,
+                                        GCMAppHandler* handler) {
+  GCMDriver::AddAppHandler(app_id, handler);
+}
+
+void CustomFakeGCMDriver::RemoveAppHandler(const std::string& app_id) {
+  GCMDriver::RemoveAppHandler(app_id);
+}
+
+void CustomFakeGCMDriver::CompleteSend(const std::string& message_id,
+                                       GCMClient::Result result) {
+  SendFinished(kGCMAccountMapperAppId, message_id, result);
+}
+
+void CustomFakeGCMDriver::SendAcknowledged(const std::string& message_id) {
+  GetAppHandler(kGCMAccountMapperAppId)
+      ->OnSendAcknowledged(kGCMAccountMapperAppId, message_id);
+}
+
+void CustomFakeGCMDriver::MessageSendError(const std::string& message_id) {
+  GCMClient::SendErrorDetails send_error;
+  send_error.message_id = message_id;
+  send_error.result = GCMClient::TTL_EXCEEDED;
+  GetAppHandler(kGCMAccountMapperAppId)
+      ->OnSendError(kGCMAccountMapperAppId, send_error);
+}
+
+void CustomFakeGCMDriver::SendImpl(const std::string& app_id,
+                                   const std::string& receiver_id,
+                                   const GCMClient::OutgoingMessage& message) {
+  DCHECK_EQ(kGCMAccountMapperAppId, app_id);
+  DCHECK_EQ(kGCMAccountMapperSenderId, receiver_id);
+
+  last_message_id_ = message.id;
+}
+
+}  // namespace
+
+class GCMAccountMapperTest : public testing::Test {
+ public:
+  GCMAccountMapperTest();
+  virtual ~GCMAccountMapperTest();
+
+  void Restart();
+
+  const std::vector<AccountMapping>& GetAccounts() const {
+    return account_mapper_->accounts_;
+  }
+
+  GCMAccountMapper* mapper() { return account_mapper_.get(); }
+
+  CustomFakeGCMDriver& gcm_driver() { return gcm_driver_; }
+
+  base::SimpleTestClock* clock() { return clock_; }
+
+ private:
+  CustomFakeGCMDriver gcm_driver_;
+  scoped_ptr<GCMAccountMapper> account_mapper_;
+  base::SimpleTestClock* clock_;
+};
+
+GCMAccountMapperTest::GCMAccountMapperTest() {
+  Restart();
+}
+
+GCMAccountMapperTest::~GCMAccountMapperTest() {
+}
+
+void GCMAccountMapperTest::Restart() {
+  if (account_mapper_)
+    account_mapper_->ShutdownHandler();
+  account_mapper_.reset(new GCMAccountMapper(&gcm_driver_));
+  scoped_ptr<base::SimpleTestClock> clock(new base::SimpleTestClock);
+  clock_ = clock.get();
+  account_mapper_->SetClockForTesting(clock.PassAs<base::Clock>());
+}
+
+// Tests the initialization of account mappings (from the store) when empty.
+TEST_F(GCMAccountMapperTest, InitializeAccountMappingsEmpty) {
+  std::vector<AccountMapping> account_mappings;
+  mapper()->Initialize(account_mappings, "");
+  EXPECT_TRUE(GetAccounts().empty());
+}
+
+// Tests the initialization of account mappings (from the store).
+TEST_F(GCMAccountMapperTest, InitializeAccountMappings) {
+  std::vector<AccountMapping> account_mappings;
+  AccountMapping account_mapping1 = MakeAccountMapping("acc_id1",
+                                                       AccountMapping::MAPPED,
+                                                       base::Time::Now(),
+                                                       std::string());
+  AccountMapping account_mapping2 = MakeAccountMapping("acc_id2",
+                                                       AccountMapping::ADDING,
+                                                       base::Time::Now(),
+                                                       "add_message_1");
+  account_mappings.push_back(account_mapping1);
+  account_mappings.push_back(account_mapping2);
+
+  mapper()->Initialize(account_mappings, "");
+
+  std::vector<AccountMapping> mappings = GetAccounts();
+  EXPECT_EQ(2UL, mappings.size());
+  std::vector<AccountMapping>::const_iterator iter = mappings.begin();
+
+  EXPECT_EQ(account_mapping1.account_id, iter->account_id);
+  EXPECT_EQ(account_mapping1.email, iter->email);
+  EXPECT_TRUE(account_mapping1.access_token.empty());
+  EXPECT_EQ(account_mapping1.status, iter->status);
+  EXPECT_EQ(account_mapping1.status_change_timestamp,
+            iter->status_change_timestamp);
+  EXPECT_TRUE(account_mapping1.last_message_id.empty());
+
+  ++iter;
+  EXPECT_EQ(account_mapping2.account_id, iter->account_id);
+  EXPECT_EQ(account_mapping2.email, iter->email);
+  EXPECT_TRUE(account_mapping2.access_token.empty());
+  EXPECT_EQ(account_mapping2.status, iter->status);
+  EXPECT_EQ(account_mapping2.status_change_timestamp,
+            iter->status_change_timestamp);
+  EXPECT_EQ(account_mapping2.last_message_id, iter->last_message_id);
+}
+
+// Tests the part where a new account is added with a token, to the point when
+// GCM message is sent.
+TEST_F(GCMAccountMapperTest, AddMappingToMessageSent) {
+  mapper()->Initialize(GCMAccountMapper::AccountMappings(), kRegistrationId);
+
+  std::vector<GCMClient::AccountTokenInfo> account_tokens;
+  GCMClient::AccountTokenInfo account_token = MakeAccountTokenInfo("acc_id");
+  account_tokens.push_back(account_token);
+  mapper()->SetAccountTokens(account_tokens);
+
+  std::vector<AccountMapping> mappings = GetAccounts();
+  EXPECT_EQ(1UL, mappings.size());
+  std::vector<AccountMapping>::const_iterator iter = mappings.begin();
+  EXPECT_EQ("acc_id", iter->account_id);
+  EXPECT_EQ("acc_id@gmail.com", iter->email);
+  EXPECT_EQ("acc_id_token", iter->access_token);
+  EXPECT_EQ(AccountMapping::NEW, iter->status);
+  EXPECT_EQ(base::Time(), iter->status_change_timestamp);
+
+  EXPECT_TRUE(!gcm_driver().last_message_id().empty());
+}
+
+// Tests the part where GCM message is successfully queued.
+TEST_F(GCMAccountMapperTest, AddMappingMessageQueued) {
+  mapper()->Initialize(GCMAccountMapper::AccountMappings(), kRegistrationId);
+
+  std::vector<GCMClient::AccountTokenInfo> account_tokens;
+  GCMClient::AccountTokenInfo account_token = MakeAccountTokenInfo("acc_id");
+  account_tokens.push_back(account_token);
+  mapper()->SetAccountTokens(account_tokens);
+
+  clock()->SetNow(base::Time::Now());
+  gcm_driver().CompleteSend(gcm_driver().last_message_id(), GCMClient::SUCCESS);
+
+  EXPECT_EQ(account_token.email, gcm_driver().last_account_mapping().email);
+  EXPECT_EQ(account_token.account_id,
+            gcm_driver().last_account_mapping().account_id);
+  EXPECT_EQ(account_token.access_token,
+            gcm_driver().last_account_mapping().access_token);
+  EXPECT_EQ(AccountMapping::ADDING, gcm_driver().last_account_mapping().status);
+  EXPECT_EQ(clock()->Now(),
+            gcm_driver().last_account_mapping().status_change_timestamp);
+  EXPECT_EQ(gcm_driver().last_message_id(),
+            gcm_driver().last_account_mapping().last_message_id);
+
+  std::vector<AccountMapping> mappings = GetAccounts();
+  std::vector<AccountMapping>::const_iterator iter = mappings.begin();
+  EXPECT_EQ(account_token.email, iter->email);
+  EXPECT_EQ(account_token.account_id, iter->account_id);
+  EXPECT_EQ(account_token.access_token, iter->access_token);
+  EXPECT_EQ(AccountMapping::ADDING, iter->status);
+  EXPECT_EQ(clock()->Now(), iter->status_change_timestamp);
+  EXPECT_EQ(gcm_driver().last_message_id(), iter->last_message_id);
+}
+
+// Tests status change from ADDING to MAPPED (Message is acknowledged).
+TEST_F(GCMAccountMapperTest, AddMappingMessageAcknowledged) {
+  mapper()->Initialize(GCMAccountMapper::AccountMappings(), kRegistrationId);
+
+  std::vector<GCMClient::AccountTokenInfo> account_tokens;
+  GCMClient::AccountTokenInfo account_token = MakeAccountTokenInfo("acc_id");
+  account_tokens.push_back(account_token);
+  mapper()->SetAccountTokens(account_tokens);
+
+  clock()->SetNow(base::Time::Now());
+  gcm_driver().CompleteSend(gcm_driver().last_message_id(), GCMClient::SUCCESS);
+  clock()->SetNow(base::Time::Now());
+  gcm_driver().SendAcknowledged(gcm_driver().last_message_id());
+
+  EXPECT_EQ(account_token.email, gcm_driver().last_account_mapping().email);
+  EXPECT_EQ(account_token.account_id,
+            gcm_driver().last_account_mapping().account_id);
+  EXPECT_EQ(account_token.access_token,
+            gcm_driver().last_account_mapping().access_token);
+  EXPECT_EQ(AccountMapping::MAPPED, gcm_driver().last_account_mapping().status);
+  EXPECT_EQ(clock()->Now(),
+            gcm_driver().last_account_mapping().status_change_timestamp);
+  EXPECT_TRUE(gcm_driver().last_account_mapping().last_message_id.empty());
+
+  std::vector<AccountMapping> mappings = GetAccounts();
+  std::vector<AccountMapping>::const_iterator iter = mappings.begin();
+  EXPECT_EQ(account_token.email, iter->email);
+  EXPECT_EQ(account_token.account_id, iter->account_id);
+  EXPECT_EQ(account_token.access_token, iter->access_token);
+  EXPECT_EQ(AccountMapping::MAPPED, iter->status);
+  EXPECT_EQ(clock()->Now(), iter->status_change_timestamp);
+  EXPECT_TRUE(iter->last_message_id.empty());
+}
+
+// Tests status change form ADDING to MAPPED (When message was acknowledged,
+// after Chrome was restarted).
+TEST_F(GCMAccountMapperTest, AddMappingMessageAckedAfterRestart) {
+  mapper()->Initialize(GCMAccountMapper::AccountMappings(), kRegistrationId);
+
+  std::vector<GCMClient::AccountTokenInfo> account_tokens;
+  GCMClient::AccountTokenInfo account_token = MakeAccountTokenInfo("acc_id");
+  account_tokens.push_back(account_token);
+  mapper()->SetAccountTokens(account_tokens);
+
+  clock()->SetNow(base::Time::Now());
+  gcm_driver().CompleteSend(gcm_driver().last_message_id(), GCMClient::SUCCESS);
+
+  Restart();
+  std::vector<AccountMapping> stored_mappings;
+  stored_mappings.push_back(gcm_driver().last_account_mapping());
+  mapper()->Initialize(stored_mappings, kRegistrationId);
+
+  clock()->SetNow(base::Time::Now());
+  gcm_driver().SendAcknowledged(gcm_driver().last_message_id());
+
+  EXPECT_EQ(account_token.email, gcm_driver().last_account_mapping().email);
+  EXPECT_EQ(account_token.account_id,
+            gcm_driver().last_account_mapping().account_id);
+  EXPECT_EQ(account_token.access_token,
+            gcm_driver().last_account_mapping().access_token);
+  EXPECT_EQ(AccountMapping::MAPPED, gcm_driver().last_account_mapping().status);
+  EXPECT_EQ(clock()->Now(),
+            gcm_driver().last_account_mapping().status_change_timestamp);
+  EXPECT_TRUE(gcm_driver().last_account_mapping().last_message_id.empty());
+
+  std::vector<AccountMapping> mappings = GetAccounts();
+  std::vector<AccountMapping>::const_iterator iter = mappings.begin();
+  EXPECT_EQ(account_token.email, iter->email);
+  EXPECT_EQ(account_token.account_id, iter->account_id);
+  EXPECT_EQ(account_token.access_token, iter->access_token);
+  EXPECT_EQ(AccountMapping::MAPPED, iter->status);
+  EXPECT_EQ(clock()->Now(), iter->status_change_timestamp);
+  EXPECT_TRUE(iter->last_message_id.empty());
+}
+
+// Tests a case when ADD message times out for a new account.
+TEST_F(GCMAccountMapperTest, AddMappingMessageSendErrorForNewAccount) {
+  mapper()->Initialize(GCMAccountMapper::AccountMappings(), kRegistrationId);
+
+  std::vector<GCMClient::AccountTokenInfo> account_tokens;
+  GCMClient::AccountTokenInfo account_token = MakeAccountTokenInfo("acc_id");
+  account_tokens.push_back(account_token);
+  mapper()->SetAccountTokens(account_tokens);
+
+  clock()->SetNow(base::Time::Now());
+  gcm_driver().CompleteSend(gcm_driver().last_message_id(), GCMClient::SUCCESS);
+
+  clock()->SetNow(base::Time::Now());
+  std::string old_message_id = gcm_driver().last_message_id();
+  gcm_driver().MessageSendError(old_message_id);
+
+  // No new message is sent because of the send error, as the token is stale.
+  // Because the account was new, the entry should be deleted.
+  EXPECT_EQ(old_message_id, gcm_driver().last_message_id());
+  EXPECT_EQ(account_token.account_id, gcm_driver().last_removed_account_id());
+  EXPECT_TRUE(GetAccounts().empty());
+}
+
+/// Tests a case when ADD message times out for a MAPPED account.
+TEST_F(GCMAccountMapperTest, AddMappingMessageSendErrorForMappedAccount) {
+  // Start with one account that is mapped.
+  base::Time status_change_timestamp = base::Time::Now();
+  AccountMapping mapping = MakeAccountMapping("acc_id",
+                                              AccountMapping::MAPPED,
+                                              status_change_timestamp,
+                                              "add_message_id");
+
+  GCMAccountMapper::AccountMappings stored_mappings;
+  stored_mappings.push_back(mapping);
+  mapper()->Initialize(stored_mappings, kRegistrationId);
+
+  clock()->SetNow(base::Time::Now());
+  gcm_driver().MessageSendError("add_message_id");
+
+  // No new message is sent because of the send error, as the token is stale.
+  // Because the account was new, the entry should be deleted.
+  EXPECT_TRUE(gcm_driver().last_message_id().empty());
+
+  std::vector<AccountMapping> mappings = GetAccounts();
+  std::vector<AccountMapping>::const_iterator iter = mappings.begin();
+  EXPECT_EQ(mapping.email, iter->email);
+  EXPECT_EQ(mapping.account_id, iter->account_id);
+  EXPECT_EQ(mapping.access_token, iter->access_token);
+  EXPECT_EQ(AccountMapping::MAPPED, iter->status);
+  EXPECT_EQ(status_change_timestamp, iter->status_change_timestamp);
+  EXPECT_TRUE(iter->last_message_id.empty());
+}
+
+// Tests that a missing token for an account will trigger removing of that
+// account. This test goes only until the message is passed to GCM.
+TEST_F(GCMAccountMapperTest, RemoveMappingToMessageSent) {
+  // Start with one account that is mapped.
+  AccountMapping mapping = MakeAccountMapping("acc_id",
+                                              AccountMapping::MAPPED,
+                                              base::Time::Now(),
+                                              std::string());
+
+  GCMAccountMapper::AccountMappings stored_mappings;
+  stored_mappings.push_back(mapping);
+  mapper()->Initialize(stored_mappings, kRegistrationId);
+  clock()->SetNow(base::Time::Now());
+
+  mapper()->SetAccountTokens(std::vector<GCMClient::AccountTokenInfo>());
+
+  EXPECT_EQ(mapping.account_id, gcm_driver().last_account_mapping().account_id);
+  EXPECT_EQ(mapping.email, gcm_driver().last_account_mapping().email);
+  EXPECT_EQ(AccountMapping::REMOVING,
+            gcm_driver().last_account_mapping().status);
+  EXPECT_EQ(clock()->Now(),
+            gcm_driver().last_account_mapping().status_change_timestamp);
+  EXPECT_TRUE(gcm_driver().last_account_mapping().last_message_id.empty());
+
+  std::vector<AccountMapping> mappings = GetAccounts();
+  std::vector<AccountMapping>::const_iterator iter = mappings.begin();
+  EXPECT_EQ(mapping.email, iter->email);
+  EXPECT_EQ(mapping.account_id, iter->account_id);
+  EXPECT_EQ(mapping.access_token, iter->access_token);
+  EXPECT_EQ(AccountMapping::REMOVING, iter->status);
+  EXPECT_EQ(clock()->Now(), iter->status_change_timestamp);
+  EXPECT_TRUE(iter->last_message_id.empty());
+}
+
+// Tests that a missing token for an account will trigger removing of that
+// account. This test goes until the message is queued by GCM.
+TEST_F(GCMAccountMapperTest, RemoveMappingMessageQueued) {
+  // Start with one account that is mapped.
+  AccountMapping mapping = MakeAccountMapping("acc_id",
+                                              AccountMapping::MAPPED,
+                                              base::Time::Now(),
+                                              std::string());
+
+  GCMAccountMapper::AccountMappings stored_mappings;
+  stored_mappings.push_back(mapping);
+  mapper()->Initialize(stored_mappings, kRegistrationId);
+  clock()->SetNow(base::Time::Now());
+  base::Time status_change_timestamp = clock()->Now();
+
+  mapper()->SetAccountTokens(std::vector<GCMClient::AccountTokenInfo>());
+  clock()->SetNow(base::Time::Now());
+  gcm_driver().CompleteSend(gcm_driver().last_message_id(), GCMClient::SUCCESS);
+
+  EXPECT_EQ(mapping.account_id, gcm_driver().last_account_mapping().account_id);
+  EXPECT_EQ(mapping.email, gcm_driver().last_account_mapping().email);
+  EXPECT_EQ(AccountMapping::REMOVING,
+            gcm_driver().last_account_mapping().status);
+  EXPECT_EQ(status_change_timestamp,
+            gcm_driver().last_account_mapping().status_change_timestamp);
+  EXPECT_TRUE(!gcm_driver().last_account_mapping().last_message_id.empty());
+
+  std::vector<AccountMapping> mappings = GetAccounts();
+  std::vector<AccountMapping>::const_iterator iter = mappings.begin();
+  EXPECT_EQ(mapping.email, iter->email);
+  EXPECT_EQ(mapping.account_id, iter->account_id);
+  EXPECT_EQ(mapping.access_token, iter->access_token);
+  EXPECT_EQ(AccountMapping::REMOVING, iter->status);
+  EXPECT_EQ(status_change_timestamp, iter->status_change_timestamp);
+  EXPECT_EQ(gcm_driver().last_account_mapping().last_message_id,
+            iter->last_message_id);
+}
+
+// Tests that a missing token for an account will trigger removing of that
+// account. This test goes until the message is acknowledged by GCM.
+// This is a complete success scenario for account removal, and it end with
+// account mapping being completely gone.
+TEST_F(GCMAccountMapperTest, RemoveMappingMessageAcknowledged) {
+  // Start with one account that is mapped.
+  AccountMapping mapping = MakeAccountMapping("acc_id",
+                                              AccountMapping::MAPPED,
+                                              base::Time::Now(),
+                                              std::string());
+
+  GCMAccountMapper::AccountMappings stored_mappings;
+  stored_mappings.push_back(mapping);
+  mapper()->Initialize(stored_mappings, kRegistrationId);
+  clock()->SetNow(base::Time::Now());
+
+  mapper()->SetAccountTokens(std::vector<GCMClient::AccountTokenInfo>());
+  gcm_driver().CompleteSend(gcm_driver().last_message_id(), GCMClient::SUCCESS);
+  gcm_driver().SendAcknowledged(gcm_driver().last_message_id());
+
+  EXPECT_EQ(mapping.account_id, gcm_driver().last_removed_account_id());
+
+  std::vector<AccountMapping> mappings = GetAccounts();
+  EXPECT_TRUE(mappings.empty());
+}
+
+// Tests that account removing proceeds, when a removing message is acked after
+// Chrome was restarted.
+TEST_F(GCMAccountMapperTest, RemoveMappingMessageAckedAfterRestart) {
+  // Start with one account that is mapped.
+  AccountMapping mapping = MakeAccountMapping("acc_id",
+                                              AccountMapping::REMOVING,
+                                              base::Time::Now(),
+                                              "remove_message_id");
+
+  GCMAccountMapper::AccountMappings stored_mappings;
+  stored_mappings.push_back(mapping);
+  mapper()->Initialize(stored_mappings, kRegistrationId);
+
+  gcm_driver().SendAcknowledged("remove_message_id");
+
+  EXPECT_EQ(mapping.account_id, gcm_driver().last_removed_account_id());
+
+  std::vector<AccountMapping> mappings = GetAccounts();
+  EXPECT_TRUE(mappings.empty());
+}
+
+// Tests that account removing proceeds, when a removing message is acked after
+// Chrome was restarted.
+TEST_F(GCMAccountMapperTest, RemoveMappingMessageSendError) {
+  // Start with one account that is mapped.
+  base::Time status_change_timestamp = base::Time::Now();
+  AccountMapping mapping = MakeAccountMapping("acc_id",
+                                              AccountMapping::REMOVING,
+                                              status_change_timestamp,
+                                              "remove_message_id");
+
+  GCMAccountMapper::AccountMappings stored_mappings;
+  stored_mappings.push_back(mapping);
+  mapper()->Initialize(stored_mappings, kRegistrationId);
+
+  clock()->SetNow(base::Time::Now());
+  gcm_driver().MessageSendError("remove_message_id");
+
+  EXPECT_TRUE(gcm_driver().last_removed_account_id().empty());
+
+  EXPECT_EQ(mapping.account_id, gcm_driver().last_account_mapping().account_id);
+  EXPECT_EQ(mapping.email, gcm_driver().last_account_mapping().email);
+  EXPECT_EQ(AccountMapping::REMOVING,
+            gcm_driver().last_account_mapping().status);
+  EXPECT_EQ(status_change_timestamp,
+            gcm_driver().last_account_mapping().status_change_timestamp);
+  // Message is not persisted, until send is completed.
+  EXPECT_TRUE(gcm_driver().last_account_mapping().last_message_id.empty());
+
+  std::vector<AccountMapping> mappings = GetAccounts();
+  std::vector<AccountMapping>::const_iterator iter = mappings.begin();
+  EXPECT_EQ(mapping.email, iter->email);
+  EXPECT_EQ(mapping.account_id, iter->account_id);
+  EXPECT_TRUE(iter->access_token.empty());
+  EXPECT_EQ(AccountMapping::REMOVING, iter->status);
+  EXPECT_EQ(status_change_timestamp, iter->status_change_timestamp);
+  EXPECT_TRUE(iter->last_message_id.empty());
+}
+
+}  // namespace gcm
diff --git a/components/gcm_driver/gcm_client.h b/components/gcm_driver/gcm_client.h
index 8a7f7b2..825c9fd 100644
--- a/components/gcm_driver/gcm_client.h
+++ b/components/gcm_driver/gcm_client.h
@@ -141,6 +141,13 @@ class GCMClient {
     RecordedActivities recorded_activities;
   };
 
+  // Information about account.
+  struct AccountTokenInfo {
+    std::string account_id;
+    std::string email;
+    std::string access_token;
+  };
+
   // A delegate interface that allows the GCMClient instance to interact with
   // its caller, i.e. notifying asynchronous event.
   class Delegate {