G-services settings v3 implementation

G-services settings v3 implementation:
* Adding calculation of settings based on a diff from server
* Adding calculation of settings digest
* Changing internal representation of settings to string->string map
  in order to be able to calculate the digest properly.
* Individual settings are calculated when needed.

R=jianli@chromium.org,zea@chromium.org
BUG=359256

Review URL: https://codereview.chromium.org/288433002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@271600 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 547 insertions, 285 deletions

diff --git a/google_apis/gcm/engine/checkin_request.cc b/google_apis/gcm/engine/checkin_request.cc
index 7b3ff22..e7490e5 100644
--- a/google_apis/gcm/engine/checkin_request.cc
+++ b/google_apis/gcm/engine/checkin_request.cc
@@ -17,7 +17,7 @@ namespace gcm {
 
 namespace {
 const char kRequestContentType[] = "application/x-protobuf";
-const int kRequestVersionValue = 2;
+const int kRequestVersionValue = 3;
 const int kDefaultUserSerialNumber = 0;
 
 // This enum is also used in an UMA histogram (GCMCheckinRequestStatus
diff --git a/google_apis/gcm/engine/gservices_settings.cc b/google_apis/gcm/engine/gservices_settings.cc
index 55cfa39..4e98972 100644
--- a/google_apis/gcm/engine/gservices_settings.cc
+++ b/google_apis/gcm/engine/gservices_settings.cc
@@ -5,7 +5,9 @@
 #include "google_apis/gcm/engine/gservices_settings.h"
 
 #include "base/bind.h"
+#include "base/sha1.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 
 namespace {
@@ -28,12 +30,142 @@ const int kDefaultMCSMainSecurePort = 5228;
 const int kDefaultMCSFallbackSecurePort = 443;
 const char kDefaultRegistrationURL[] =
     "https://android.clients.google.com/c2dm/register3";
+// Settings that are to be deleted are marked with this prefix in checkin
+// response.
+const char kDeleteSettingPrefix[] = "delete_";
+// Settings digest starts with verison number followed by '-'.
+const char kDigestVersionPrefix[] = "1-";
 const char kMCSEnpointTemplate[] = "https://%s:%d";
+const int kMaxSecurePort = 65535;
 
 std::string MakeMCSEndpoint(const std::string& mcs_hostname, int port) {
   return base::StringPrintf(kMCSEnpointTemplate, mcs_hostname.c_str(), port);
 }
 
+// Default settings can be omitted, as GServicesSettings class provides
+// reasonable defaults.
+bool CanBeOmitted(const std::string& settings_name) {
+  return settings_name == kCheckinIntervalKey ||
+         settings_name == kCheckinURLKey ||
+         settings_name == kMCSHostnameKey ||
+         settings_name == kMCSSecurePortKey ||
+         settings_name == kRegistrationURLKey;
+}
+
+bool VerifyCheckinInterval(
+    const gcm::GServicesSettings::SettingsMap& settings) {
+  gcm::GServicesSettings::SettingsMap::const_iterator iter =
+      settings.find(kCheckinIntervalKey);
+  if (iter == settings.end())
+    return CanBeOmitted(kCheckinIntervalKey);
+
+  int64 checkin_interval = kMinimumCheckinInterval;
+  if (!base::StringToInt64(iter->second, &checkin_interval)) {
+    DVLOG(1) << "Failed to parse checkin interval: " << iter->second;
+    return false;
+  }
+  if (checkin_interval == std::numeric_limits<int64>::max()) {
+    DVLOG(1) << "Checkin interval is too big: " << checkin_interval;
+    return false;
+  }
+  if (checkin_interval < kMinimumCheckinInterval) {
+    DVLOG(1) << "Checkin interval: " << checkin_interval
+             << " is less than allowed minimum: " << kMinimumCheckinInterval;
+  }
+
+  return true;
+}
+
+bool VerifyMCSEndpoint(const gcm::GServicesSettings::SettingsMap& settings) {
+  std::string mcs_hostname;
+  gcm::GServicesSettings::SettingsMap::const_iterator iter =
+      settings.find(kMCSHostnameKey);
+  if (iter == settings.end()) {
+    // Because endpoint has 2 parts (hostname and port) we are defaulting and
+    // moving on with verification.
+    if (CanBeOmitted(kMCSHostnameKey))
+      mcs_hostname = kDefaultMCSHostname;
+    else
+      return false;
+  } else if (iter->second.empty()) {
+    DVLOG(1) << "Empty MCS hostname provided.";
+    return false;
+  } else {
+    mcs_hostname = iter->second;
+  }
+
+  int mcs_secure_port = 0;
+  iter = settings.find(kMCSSecurePortKey);
+  if (iter == settings.end()) {
+    // Simlarly we might have to default the port, when only hostname is
+    // provided.
+    if (CanBeOmitted(kMCSSecurePortKey))
+      mcs_secure_port = kDefaultMCSMainSecurePort;
+    else
+      return false;
+  } else if (!base::StringToInt(iter->second, &mcs_secure_port)) {
+    DVLOG(1) << "Failed to parse MCS secure port: " << iter->second;
+    return false;
+  }
+
+  if (mcs_secure_port < 0 || mcs_secure_port > kMaxSecurePort) {
+    DVLOG(1) << "Incorrect port value: " << mcs_secure_port;
+    return false;
+  }
+
+  GURL mcs_main_endpoint(MakeMCSEndpoint(mcs_hostname, mcs_secure_port));
+  if (!mcs_main_endpoint.is_valid()) {
+    DVLOG(1) << "Invalid main MCS endpoint: "
+             << mcs_main_endpoint.possibly_invalid_spec();
+    return false;
+  }
+  GURL mcs_fallback_endpoint(
+      MakeMCSEndpoint(mcs_hostname, kDefaultMCSFallbackSecurePort));
+  if (!mcs_fallback_endpoint.is_valid()) {
+    DVLOG(1) << "Invalid fallback MCS endpoint: "
+             << mcs_fallback_endpoint.possibly_invalid_spec();
+    return false;
+  }
+
+  return true;
+}
+
+bool VerifyCheckinURL(const gcm::GServicesSettings::SettingsMap& settings) {
+  gcm::GServicesSettings::SettingsMap::const_iterator iter =
+      settings.find(kCheckinURLKey);
+  if (iter == settings.end())
+    return CanBeOmitted(kCheckinURLKey);
+
+  GURL checkin_url(iter->second);
+  if (!checkin_url.is_valid()) {
+    DVLOG(1) << "Invalid checkin URL provided: " << iter->second;
+    return false;
+  }
+
+  return true;
+}
+
+bool VerifyRegistrationURL(
+    const gcm::GServicesSettings::SettingsMap& settings) {
+  gcm::GServicesSettings::SettingsMap::const_iterator iter =
+      settings.find(kRegistrationURLKey);
+  if (iter == settings.end())
+    return CanBeOmitted(kRegistrationURLKey);
+
+  GURL registration_url(iter->second);
+  if (!registration_url.is_valid()) {
+    DVLOG(1) << "Invalid registration URL provided: " << iter->second;
+    return false;
+  }
+
+  return true;
+}
+
+bool VerifySettings(const gcm::GServicesSettings::SettingsMap& settings) {
+  return VerifyCheckinInterval(settings) && VerifyMCSEndpoint(settings) &&
+         VerifyCheckinURL(settings) && VerifyRegistrationURL(settings);
+}
+
 }  // namespace
 
 namespace gcm {
@@ -48,152 +180,163 @@ const GURL GServicesSettings::DefaultCheckinURL() {
   return GURL(kDefaultCheckinURL);
 }
 
-GServicesSettings::GServicesSettings()
-    : checkin_interval_(base::TimeDelta::FromSeconds(kDefaultCheckinInterval)),
-      checkin_url_(kDefaultCheckinURL),
-      mcs_main_endpoint_(MakeMCSEndpoint(kDefaultMCSHostname,
-                                         kDefaultMCSMainSecurePort)),
-      mcs_fallback_endpoint_(MakeMCSEndpoint(kDefaultMCSHostname,
-                                             kDefaultMCSFallbackSecurePort)),
-      registration_url_(kDefaultRegistrationURL),
-      weak_ptr_factory_(this) {
+// static
+std::string GServicesSettings::CalculateDigest(const SettingsMap& settings) {
+  unsigned char hash[base::kSHA1Length];
+  std::string data;
+  for (SettingsMap::const_iterator iter = settings.begin();
+       iter != settings.end();
+       ++iter) {
+    data += iter->first;
+    data += '\0';
+    data += iter->second;
+    data += '\0';
+  }
+  base::SHA1HashBytes(
+      reinterpret_cast<const unsigned char*>(&data[0]), data.size(), hash);
+  std::string digest =
+      kDigestVersionPrefix + base::HexEncode(hash, base::kSHA1Length);
+  digest = StringToLowerASCII(digest);
+  return digest;
+}
+
+GServicesSettings::GServicesSettings() : weak_ptr_factory_(this) {
+  digest_ = CalculateDigest(settings_);
 }
 
-GServicesSettings::~GServicesSettings() {}
+GServicesSettings::~GServicesSettings() {
+}
 
 bool GServicesSettings::UpdateFromCheckinResponse(
-  const checkin_proto::AndroidCheckinResponse& checkin_response) {
-  if (!checkin_response.has_digest() ||
-      checkin_response.digest() == digest_) {
-    // There are no changes as digest is the same or no settings provided.
+    const checkin_proto::AndroidCheckinResponse& checkin_response) {
+  if (!checkin_response.has_settings_diff()) {
+    DVLOG(1) << "Field settings_diff not set in response.";
     return false;
   }
 
-  std::map<std::string, std::string> settings;
+  bool settings_diff = checkin_response.settings_diff();
+  SettingsMap new_settings;
+  // Only reuse the existing settings, if we are given a settings difference.
+  if (settings_diff)
+    new_settings = settings_map();
+
   for (int i = 0; i < checkin_response.setting_size(); ++i) {
     std::string name = checkin_response.setting(i).name();
-    std::string value = checkin_response.setting(i).value();
-    settings[name] = value;
-  }
+    if (name.empty()) {
+      DVLOG(1) << "Setting name is empty";
+      return false;
+    }
 
-  // Only update the settings in store and digest, if the settings actually
-  // passed the verificaiton in update settings.
-  if (UpdateSettings(settings)) {
-    digest_ = checkin_response.digest();
-    return true;
+    if (settings_diff && name.find(kDeleteSettingPrefix) == 0) {
+      std::string setting_to_delete =
+          name.substr(arraysize(kDeleteSettingPrefix) - 1);
+      new_settings.erase(setting_to_delete);
+      DVLOG(1) << "Setting deleted: " << setting_to_delete;
+    } else {
+      std::string value = checkin_response.setting(i).value();
+      new_settings[name] = value;
+      DVLOG(1) << "New setting: '" << name << "' : '" << value << "'";
+    }
   }
 
-  return false;
+  if (!VerifySettings(new_settings))
+    return false;
+
+  settings_.swap(new_settings);
+  digest_ = CalculateDigest(settings_);
+  return true;
 }
 
 void GServicesSettings::UpdateFromLoadResult(
     const GCMStore::LoadResult& load_result) {
-  if (UpdateSettings(load_result.gservices_settings))
-    digest_ = load_result.gservices_digest;
-}
+  // No need to try to update settings when load_result is empty.
+  if (load_result.gservices_settings.empty())
+    return;
+  if (!VerifySettings(load_result.gservices_settings))
+    return;
+  std::string digest = CalculateDigest(load_result.gservices_settings);
+  if (digest != load_result.gservices_digest) {
+    DVLOG(1) << "G-services settings digest mismatch. "
+             << "Expected digest: " << load_result.gservices_digest
+             << ". Calculated digest is: " << digest;
+    return;
+  }
 
-std::map<std::string, std::string> GServicesSettings::GetSettingsMap() const {
-  std::map<std::string, std::string> settings;
-  settings[kCheckinIntervalKey] =
-      base::Int64ToString(checkin_interval_.InSeconds());
-  settings[kCheckinURLKey] = checkin_url_.spec();
-  settings[kMCSHostnameKey] = mcs_main_endpoint_.host();
-  settings[kMCSSecurePortKey] = mcs_main_endpoint_.port();
-  settings[kRegistrationURLKey] = registration_url_.spec();
-  return settings;
+  settings_ = load_result.gservices_settings;
+  digest_ = load_result.gservices_digest;
 }
 
-bool GServicesSettings::UpdateSettings(
-    const std::map<std::string, std::string>& settings) {
-  int64 new_checkin_interval = kMinimumCheckinInterval;
-  std::map<std::string, std::string>::const_iterator iter =
-      settings.find(kCheckinIntervalKey);
-  if (iter == settings.end()) {
-    LOG(ERROR) << "Setting not found: " << kCheckinIntervalKey;
-    return false;
-  }
-  if (!base::StringToInt64(iter->second, &new_checkin_interval)) {
-    LOG(ERROR) << "Failed to parse checkin interval: " << iter->second;
-    return false;
-  }
-  if (new_checkin_interval < kMinimumCheckinInterval) {
-    LOG(ERROR) << "Checkin interval: " << new_checkin_interval
-               << " is less than allowed minimum: " << kMinimumCheckinInterval;
-    new_checkin_interval = kMinimumCheckinInterval;
-  }
-  if (new_checkin_interval == std::numeric_limits<int64>::max()) {
-    LOG(ERROR) << "Checkin interval is too big: " << new_checkin_interval;
-    return false;
+base::TimeDelta GServicesSettings::GetCheckinInterval() const {
+  int64 checkin_interval = kMinimumCheckinInterval;
+  SettingsMap::const_iterator iter = settings_.find(kCheckinIntervalKey);
+  if (iter == settings_.end() ||
+      !base::StringToInt64(iter->second, &checkin_interval)) {
+    checkin_interval = kDefaultCheckinInterval;
   }
 
-  std::string new_mcs_hostname;
-  iter = settings.find(kMCSHostnameKey);
-  if (iter == settings.end()) {
-    LOG(ERROR) << "Setting not found: " << kMCSHostnameKey;
-    return false;
-  }
-  new_mcs_hostname = iter->second;
-  if (new_mcs_hostname.empty()) {
-    LOG(ERROR) << "Empty MCS hostname provided.";
-    return false;
-  }
+  if (checkin_interval < kMinimumCheckinInterval)
+    checkin_interval = kMinimumCheckinInterval;
 
-  int new_mcs_secure_port = -1;
-  iter = settings.find(kMCSSecurePortKey);
-  if (iter == settings.end()) {
-    LOG(ERROR) << "Setting not found: " << kMCSSecurePortKey;
-    return false;
-  }
-  if (!base::StringToInt(iter->second, &new_mcs_secure_port)) {
-    LOG(ERROR) << "Failed to parse MCS secure port: " << iter->second;
-    return false;
-  }
-  if (new_mcs_secure_port < 0 || 65535 < new_mcs_secure_port) {
-    LOG(ERROR) << "Incorrect port value: " << new_mcs_secure_port;
-    return false;
-  }
+  return base::TimeDelta::FromSeconds(checkin_interval);
+}
 
-  GURL new_mcs_main_endpoint =
-      GURL(MakeMCSEndpoint(new_mcs_hostname, new_mcs_secure_port));
-  GURL new_mcs_fallback_endpoint =
-      GURL(MakeMCSEndpoint(new_mcs_hostname, kDefaultMCSFallbackSecurePort));
-  if (!new_mcs_main_endpoint.is_valid() ||
-      !new_mcs_fallback_endpoint.is_valid())
-    return false;
+GURL GServicesSettings::GetCheckinURL() const {
+  SettingsMap::const_iterator iter = settings_.find(kCheckinURLKey);
+  if (iter == settings_.end() || iter->second.empty())
+    return GURL(kDefaultCheckinURL);
+  return GURL(iter->second);
+}
 
-  GURL new_checkin_url;
-  iter = settings.find(kCheckinURLKey);
-  if (iter == settings.end()) {
-    LOG(ERROR) << "Setting not found: " << kCheckinURLKey;
-    return false;
-  }
-  new_checkin_url = GURL(iter->second);
-  if (!new_checkin_url.is_valid()) {
-    LOG(ERROR) << "Invalid checkin URL provided: "
-               << new_checkin_url.possibly_invalid_spec();
-    return false;
-  }
+GURL GServicesSettings::GetMCSMainEndpoint() const {
+  // Get alternative hostname or use default.
+  std::string mcs_hostname;
+  SettingsMap::const_iterator iter = settings_.find(kMCSHostnameKey);
+  if (iter != settings_.end() && !iter->second.empty())
+    mcs_hostname = iter->second;
+  else
+    mcs_hostname = kDefaultMCSHostname;
 
-  GURL new_registration_url;
-  iter = settings.find(kRegistrationURLKey);
-  if (iter == settings.end()) {
-    LOG(ERROR) << "Setting not found: " << kRegistrationURLKey;
-    return false;
-  }
-  new_registration_url = GURL(iter->second);
-  if (!new_registration_url.is_valid()) {
-    LOG(ERROR) << "Invalid registration URL provided: "
-               << new_registration_url.possibly_invalid_spec();
-    return false;
+  // Get alternative secure port or use defualt.
+  int mcs_secure_port = 0;
+  iter = settings_.find(kMCSSecurePortKey);
+  if (iter == settings_.end() || iter->second.empty() ||
+      !base::StringToInt(iter->second, &mcs_secure_port)) {
+    mcs_secure_port = kDefaultMCSMainSecurePort;
   }
 
-  // We only update the settings once all of them are correct.
-  checkin_interval_ = base::TimeDelta::FromSeconds(new_checkin_interval);
-  mcs_main_endpoint_ = new_mcs_main_endpoint;
-  mcs_fallback_endpoint_ = new_mcs_fallback_endpoint;
-  checkin_url_ = new_checkin_url;
-  registration_url_ = new_registration_url;
-  return true;
+  // If constructed address makes sense use it.
+  GURL mcs_endpoint(MakeMCSEndpoint(mcs_hostname, mcs_secure_port));
+  if (mcs_endpoint.is_valid())
+    return mcs_endpoint;
+
+  // Otherwise use default settings.
+  return GURL(MakeMCSEndpoint(kDefaultMCSHostname, kDefaultMCSMainSecurePort));
+}
+
+GURL GServicesSettings::GetMCSFallbackEndpoint() const {
+  // Get alternative hostname or use default.
+  std::string mcs_hostname;
+  SettingsMap::const_iterator iter = settings_.find(kMCSHostnameKey);
+  if (iter != settings_.end() && !iter->second.empty())
+    mcs_hostname = iter->second;
+  else
+    mcs_hostname = kDefaultMCSHostname;
+
+  // If constructed address makes sense use it.
+  GURL mcs_endpoint(
+      MakeMCSEndpoint(mcs_hostname, kDefaultMCSFallbackSecurePort));
+  if (mcs_endpoint.is_valid())
+    return mcs_endpoint;
+
+  return GURL(
+      MakeMCSEndpoint(kDefaultMCSHostname, kDefaultMCSFallbackSecurePort));
+}
+
+GURL GServicesSettings::GetRegistrationURL() const {
+  SettingsMap::const_iterator iter = settings_.find(kRegistrationURLKey);
+  if (iter == settings_.end() || iter->second.empty())
+    return GURL(kDefaultRegistrationURL);
+  return GURL(iter->second);
 }
 
 }  // namespace gcm
diff --git a/google_apis/gcm/engine/gservices_settings.h b/google_apis/gcm/engine/gservices_settings.h
index 7961ca2..d3aeeb0 100644
--- a/google_apis/gcm/engine/gservices_settings.h
+++ b/google_apis/gcm/engine/gservices_settings.h
@@ -21,12 +21,17 @@ namespace gcm {
 // extracting them from checkin response and storing in GCMStore.
 class GCM_EXPORT GServicesSettings {
  public:
+  typedef std::map<std::string, std::string> SettingsMap;
+
   // Minimum periodic checkin interval in seconds.
   static const base::TimeDelta MinimumCheckinInterval();
 
   // Default checkin URL.
   static const GURL DefaultCheckinURL();
 
+  // Calculates digest of provided settings.
+  static std::string CalculateDigest(const SettingsMap& settings);
+
   GServicesSettings();
   ~GServicesSettings();
 
@@ -38,45 +43,33 @@ class GCM_EXPORT GServicesSettings {
   // successful, false otherwise.
   void UpdateFromLoadResult(const GCMStore::LoadResult& load_result);
 
-  // Gets the settings as a map of string to string for storing.
-  std::map<std::string, std::string> GetSettingsMap() const;
+  SettingsMap settings_map() const { return settings_; }
 
   std::string digest() const { return digest_; }
 
-  base::TimeDelta checkin_interval() const { return checkin_interval_; }
+  // Gets the interval at which device should perform a checkin.
+  base::TimeDelta GetCheckinInterval() const;
 
-  GURL checkin_url() const { return checkin_url_; }
+  // Gets the URL to use when checking in.
+  GURL GetCheckinURL() const;
 
-  GURL mcs_main_endpoint() const { return mcs_main_endpoint_; }
+  // Gets address of main MCS endpoint.
+  GURL GetMCSMainEndpoint() const;
 
-  GURL mcs_fallback_endpoint() const { return mcs_fallback_endpoint_; }
+  // Gets address of fallback MCS endpoint.
+  GURL GetMCSFallbackEndpoint() const;
 
-  GURL registration_url() const { return registration_url_; }
+  // Gets the URL to use when registering or unregistering the apps.
+  GURL GetRegistrationURL() const;
 
  private:
-  // Parses the |settings| to fill in specific fields.
-  // TODO(fgorski): Change to a status variable that can be logged to UMA.
-  bool UpdateSettings(const std::map<std::string, std::string>& settings);
-
   // Digest (hash) of the settings, used to check whether settings need update.
   // It is meant to be sent with checkin request, instead of sending the whole
   // settings table.
   std::string digest_;
 
-  // Time delta between periodic checkins.
-  base::TimeDelta checkin_interval_;
-
-  // URL that should be used for checkins.
-  GURL checkin_url_;
-
-  // Main MCS endpoint.
-  GURL mcs_main_endpoint_;
-
-  // Fallback MCS endpoint.
-  GURL mcs_fallback_endpoint_;
-
-  // URL that should be used for regisrations and unregistrations.
-  GURL registration_url_;
+  // G-services settings as provided by checkin response.
+  SettingsMap settings_;
 
   // Factory for creating references in callbacks.
   base::WeakPtrFactory<GServicesSettings> weak_ptr_factory_;
diff --git a/google_apis/gcm/engine/gservices_settings_unittest.cc b/google_apis/gcm/engine/gservices_settings_unittest.cc
index 12623e3..0b2d063 100644
--- a/google_apis/gcm/engine/gservices_settings_unittest.cc
+++ b/google_apis/gcm/engine/gservices_settings_unittest.cc
@@ -23,6 +23,24 @@ const int64 kDefaultCheckinInterval = 2 * 24 * 60 * 60;  // seconds = 2 days.
 const char kDefaultCheckinURL[] = "https://android.clients.google.com/checkin";
 const char kDefaultRegistrationURL[] =
     "https://android.clients.google.com/c2dm/register3";
+const char kDefaultSettingsDigest[] =
+    "1-da39a3ee5e6b4b0d3255bfef95601890afd80709";
+const char kAlternativeSettingsDigest[] =
+    "1-7da4aa4eb38a8bd3e330e3751cc0899924499134";
+
+void AddSettingsToResponse(
+    checkin_proto::AndroidCheckinResponse& checkin_response,
+    const GServicesSettings::SettingsMap& settings,
+    bool settings_diff) {
+  for (GServicesSettings::SettingsMap::const_iterator iter = settings.begin();
+       iter != settings.end();
+       ++iter) {
+    checkin_proto::GservicesSetting* setting = checkin_response.add_setting();
+    setting->set_name(iter->first);
+    setting->set_value(iter->second);
+  }
+  checkin_response.set_settings_diff(settings_diff);
+}
 
 }  // namespace
 
@@ -31,23 +49,12 @@ class GServicesSettingsTest : public testing::Test {
   GServicesSettingsTest();
   virtual ~GServicesSettingsTest();
 
-  virtual void SetUp() OVERRIDE;
-
   void CheckAllSetToDefault();
-  void CheckAllSetToAlternative();
-  void SetWithAlternativeSettings(
-      checkin_proto::AndroidCheckinResponse& checkin_response);
 
   GServicesSettings& settings() {
     return gserivces_settings_;
   }
 
-  const std::map<std::string, std::string>& alternative_settings() {
-    return alternative_settings_;
-  }
-
-  std::map<std::string, std::string> alternative_settings_;
-
  private:
   GServicesSettings gserivces_settings_;
 };
@@ -58,159 +65,273 @@ GServicesSettingsTest::GServicesSettingsTest()
 
 GServicesSettingsTest::~GServicesSettingsTest() {}
 
-void GServicesSettingsTest::SetUp() {
-  alternative_settings_["checkin_interval"] =
-      base::Int64ToString(kAlternativeCheckinInterval);
-  alternative_settings_["checkin_url"] = kAlternativeCheckinURL;
-  alternative_settings_["gcm_hostname"] = kAlternativeMCSHostname;
-  alternative_settings_["gcm_secure_port"] =
-      base::IntToString(kAlternativeMCSSecurePort);
-  alternative_settings_["gcm_registration_url"] = kAlternativeRegistrationURL;
-}
-
 void GServicesSettingsTest::CheckAllSetToDefault() {
   EXPECT_EQ(base::TimeDelta::FromSeconds(kDefaultCheckinInterval),
-            settings().checkin_interval());
-  EXPECT_EQ(GURL(kDefaultCheckinURL), settings().checkin_url());
+            settings().GetCheckinInterval());
+  EXPECT_EQ(GURL(kDefaultCheckinURL), settings().GetCheckinURL());
   EXPECT_EQ(GURL("https://mtalk.google.com:5228"),
-                 settings().mcs_main_endpoint());
+            settings().GetMCSMainEndpoint());
   EXPECT_EQ(GURL("https://mtalk.google.com:443"),
-                 settings().mcs_fallback_endpoint());
-  EXPECT_EQ(GURL(kDefaultRegistrationURL), settings().registration_url());
-}
-
-void GServicesSettingsTest::CheckAllSetToAlternative() {
-  EXPECT_EQ(base::TimeDelta::FromSeconds(kAlternativeCheckinInterval),
-            settings().checkin_interval());
-  EXPECT_EQ(GURL(kAlternativeCheckinURL), settings().checkin_url());
-  EXPECT_EQ(GURL("https://alternative.gcm.host:7777"),
-                 settings().mcs_main_endpoint());
-  EXPECT_EQ(GURL("https://alternative.gcm.host:443"),
-                 settings().mcs_fallback_endpoint());
-  EXPECT_EQ(GURL(kAlternativeRegistrationURL), settings().registration_url());
-}
-
-void GServicesSettingsTest::SetWithAlternativeSettings(
-    checkin_proto::AndroidCheckinResponse& checkin_response) {
-  for (std::map<std::string, std::string>::const_iterator iter =
-           alternative_settings_.begin();
-       iter != alternative_settings_.end(); ++iter) {
-    checkin_proto::GservicesSetting* setting = checkin_response.add_setting();
-    setting->set_name(iter->first);
-    setting->set_value(iter->second);
-  }
+            settings().GetMCSFallbackEndpoint());
+  EXPECT_EQ(GURL(kDefaultRegistrationURL), settings().GetRegistrationURL());
 }
 
 // Verifies default values of the G-services settings and settings digest.
 TEST_F(GServicesSettingsTest, DefaultSettingsAndDigest) {
   CheckAllSetToDefault();
-  EXPECT_EQ(std::string(), settings().digest());
+  EXPECT_EQ(kDefaultSettingsDigest, settings().digest());
+  EXPECT_EQ(kDefaultSettingsDigest,
+            GServicesSettings::CalculateDigest(settings().settings_map()));
+}
+
+// Verifies digest calculation for the sample provided by protocol owners.
+TEST_F(GServicesSettingsTest, CalculateDigest) {
+  GServicesSettings::SettingsMap settings_map;
+  settings_map["android_id"] = "55XXXXXXXXXXXXXXXX0";
+  settings_map["checkin_interval"] = "86400";
+  settings_map["checkin_url"] =
+      "https://fake.address.google.com/canary/checkin";
+  settings_map["chrome_device"] = "1";
+  settings_map["device_country"] = "us";
+  settings_map["gcm_hostname"] = "fake.address.google.com";
+  settings_map["gcm_secure_port"] = "443";
+
+  EXPECT_EQ("1-33381ccd1cf5791dc0e6dfa234266fa9f1259197",
+            GServicesSettings::CalculateDigest(settings_map));
 }
 
 // Verifies that settings are not updated when load result is empty.
 TEST_F(GServicesSettingsTest, UpdateFromEmptyLoadResult) {
   GCMStore::LoadResult result;
-  result.gservices_digest = "digest_value";
+  result.gservices_digest = "";
   settings().UpdateFromLoadResult(result);
 
   CheckAllSetToDefault();
-  EXPECT_EQ(std::string(), settings().digest());
+  EXPECT_EQ(kDefaultSettingsDigest, settings().digest());
 }
 
-// Verifies that settings are not updated when one of them is missing.
+// Verifies that settings are not when digest value does not match.
 TEST_F(GServicesSettingsTest, UpdateFromLoadResultWithSettingMissing) {
   GCMStore::LoadResult result;
-  result.gservices_settings = alternative_settings();
+  result.gservices_settings["checkin_internval"] = "100000";
   result.gservices_digest = "digest_value";
-  result.gservices_settings.erase("gcm_hostname");
   settings().UpdateFromLoadResult(result);
 
   CheckAllSetToDefault();
-  EXPECT_EQ(std::string(), settings().digest());
+  EXPECT_EQ(kDefaultSettingsDigest, settings().digest());
 }
 
 // Verifies that the settings are set correctly based on the load result.
 TEST_F(GServicesSettingsTest, UpdateFromLoadResult) {
   GCMStore::LoadResult result;
-  result.gservices_settings = alternative_settings();
-  result.gservices_digest = "digest_value";
+  result.gservices_settings["checkin_interval"] =
+      base::Int64ToString(kAlternativeCheckinInterval);
+  result.gservices_settings["checkin_url"] = kAlternativeCheckinURL;
+  result.gservices_settings["gcm_hostname"] = kAlternativeMCSHostname;
+  result.gservices_settings["gcm_secure_port"] =
+      base::IntToString(kAlternativeMCSSecurePort);
+  result.gservices_settings["gcm_registration_url"] =
+      kAlternativeRegistrationURL;
+  result.gservices_digest = kAlternativeSettingsDigest;
   settings().UpdateFromLoadResult(result);
 
-  CheckAllSetToAlternative();
-  EXPECT_EQ("digest_value", settings().digest());
+  EXPECT_EQ(base::TimeDelta::FromSeconds(kAlternativeCheckinInterval),
+            settings().GetCheckinInterval());
+  EXPECT_EQ(GURL(kAlternativeCheckinURL), settings().GetCheckinURL());
+  EXPECT_EQ(GURL("https://alternative.gcm.host:7777"),
+            settings().GetMCSMainEndpoint());
+  EXPECT_EQ(GURL("https://alternative.gcm.host:443"),
+            settings().GetMCSFallbackEndpoint());
+  EXPECT_EQ(GURL(kAlternativeRegistrationURL), settings().GetRegistrationURL());
+  EXPECT_EQ(GServicesSettings::CalculateDigest(result.gservices_settings),
+            settings().digest());
 }
 
-// Verifies that the settings are set correctly after parsing a checkin
-// response.
-TEST_F(GServicesSettingsTest, UpdateFromCheckinResponse) {
+// Verifies that the checkin interval is updated to minimum if the original
+// value is less than minimum.
+TEST_F(GServicesSettingsTest, CheckinResponseMinimumCheckinInterval) {
+  // Setting the checkin interval to less than minimum.
   checkin_proto::AndroidCheckinResponse checkin_response;
-
-  checkin_response.set_digest("digest_value");
-  SetWithAlternativeSettings(checkin_response);
+  GServicesSettings::SettingsMap new_settings;
+  new_settings["checkin_interval"] = "3600";
+  AddSettingsToResponse(checkin_response, new_settings, false);
 
   EXPECT_TRUE(settings().UpdateFromCheckinResponse(checkin_response));
 
-  CheckAllSetToAlternative();
-  EXPECT_EQ(alternative_settings_, settings().GetSettingsMap());
-  EXPECT_EQ("digest_value", settings().digest());
+  EXPECT_EQ(GServicesSettings::MinimumCheckinInterval(),
+            settings().GetCheckinInterval());
+  EXPECT_EQ(GServicesSettings::CalculateDigest(new_settings),
+            settings().digest());
 }
 
-// Verifies that the checkin interval is updated to minimum if the original
-// value is less than minimum.
-TEST_F(GServicesSettingsTest, UpdateFromCheckinResponseMinimumCheckinInterval) {
+// Verifies that default checkin interval can be selectively overwritten.
+TEST_F(GServicesSettingsTest, CheckinResponseUpdateCheckinInterval) {
   checkin_proto::AndroidCheckinResponse checkin_response;
+  GServicesSettings::SettingsMap new_settings;
+  new_settings["checkin_interval"] = "86400";
+  AddSettingsToResponse(checkin_response, new_settings, false);
 
-  checkin_response.set_digest("digest_value");
-  // Setting the checkin interval to less than minimum.
-  alternative_settings_["checkin_interval"] = base::IntToString(3600);
-  SetWithAlternativeSettings(checkin_response);
+  EXPECT_TRUE(settings().UpdateFromCheckinResponse(checkin_response));
+
+  // Only the checkin interval was updated:
+  EXPECT_EQ(base::TimeDelta::FromSeconds(86400),
+            settings().GetCheckinInterval());
+
+  // Other settings still set to default.
+  EXPECT_EQ(GURL("https://mtalk.google.com:5228"),
+            settings().GetMCSMainEndpoint());
+  EXPECT_EQ(GURL("https://mtalk.google.com:443"),
+            settings().GetMCSFallbackEndpoint());
+  EXPECT_EQ(GURL(kDefaultCheckinURL), settings().GetCheckinURL());
+  EXPECT_EQ(GURL(kDefaultRegistrationURL), settings().GetRegistrationURL());
+
+  EXPECT_EQ(GServicesSettings::CalculateDigest(new_settings),
+            settings().digest());
+}
+
+// Verifies that default registration URL can be selectively overwritten.
+TEST_F(GServicesSettingsTest, CheckinResponseUpdateRegistrationURL) {
+  checkin_proto::AndroidCheckinResponse checkin_response;
+  GServicesSettings::SettingsMap new_settings;
+  new_settings["gcm_registration_url"] = "https://new.registration.url";
+  AddSettingsToResponse(checkin_response, new_settings, false);
 
   EXPECT_TRUE(settings().UpdateFromCheckinResponse(checkin_response));
 
-  EXPECT_EQ(GServicesSettings::MinimumCheckinInterval(),
-            settings().checkin_interval());
-  EXPECT_EQ("digest_value", settings().digest());
+  // Only the registration URL was updated:
+  EXPECT_EQ(GURL("https://new.registration.url"),
+            settings().GetRegistrationURL());
+
+  // Other settings still set to default.
+  EXPECT_EQ(base::TimeDelta::FromSeconds(kDefaultCheckinInterval),
+            settings().GetCheckinInterval());
+  EXPECT_EQ(GURL("https://mtalk.google.com:5228"),
+            settings().GetMCSMainEndpoint());
+  EXPECT_EQ(GURL("https://mtalk.google.com:443"),
+            settings().GetMCSFallbackEndpoint());
+  EXPECT_EQ(GURL(kDefaultCheckinURL), settings().GetCheckinURL());
+
+  EXPECT_EQ(GServicesSettings::CalculateDigest(new_settings),
+            settings().digest());
 }
 
-// Verifies that settings are not updated when one of them is missing.
-TEST_F(GServicesSettingsTest, UpdateFromCheckinResponseWithSettingMissing) {
+// Verifies that default checkin URL can be selectively overwritten.
+TEST_F(GServicesSettingsTest, CheckinResponseUpdateCheckinURL) {
   checkin_proto::AndroidCheckinResponse checkin_response;
+  GServicesSettings::SettingsMap new_settings;
+  new_settings["checkin_url"] = "https://new.checkin.url";
+  AddSettingsToResponse(checkin_response, new_settings, false);
 
-  checkin_response.set_digest("digest_value");
-  alternative_settings_.erase("gcm_hostname");
-  SetWithAlternativeSettings(checkin_response);
+  EXPECT_TRUE(settings().UpdateFromCheckinResponse(checkin_response));
 
-  EXPECT_FALSE(settings().UpdateFromCheckinResponse(checkin_response));
+  // Only the checkin URL was updated:
+  EXPECT_EQ(GURL("https://new.checkin.url"), settings().GetCheckinURL());
 
-  CheckAllSetToDefault();
-  EXPECT_EQ(std::string(), settings().digest());
+  // Other settings still set to default.
+  EXPECT_EQ(base::TimeDelta::FromSeconds(kDefaultCheckinInterval),
+            settings().GetCheckinInterval());
+  EXPECT_EQ(GURL("https://mtalk.google.com:5228"),
+            settings().GetMCSMainEndpoint());
+  EXPECT_EQ(GURL("https://mtalk.google.com:443"),
+            settings().GetMCSFallbackEndpoint());
+  EXPECT_EQ(GURL(kDefaultRegistrationURL), settings().GetRegistrationURL());
+
+  EXPECT_EQ(GServicesSettings::CalculateDigest(new_settings),
+            settings().digest());
 }
 
-// Verifies that no update is done, when a checkin response misses digest.
-TEST_F(GServicesSettingsTest, UpdateFromCheckinResponseNoDigest) {
+// Verifies that default MCS hostname can be selectively overwritten.
+TEST_F(GServicesSettingsTest, CheckinResponseUpdateMCSHostname) {
   checkin_proto::AndroidCheckinResponse checkin_response;
+  GServicesSettings::SettingsMap new_settings;
+  new_settings["gcm_hostname"] = "new.gcm.hostname";
+  AddSettingsToResponse(checkin_response, new_settings, false);
 
-  SetWithAlternativeSettings(checkin_response);
-  EXPECT_FALSE(settings().UpdateFromCheckinResponse(checkin_response));
+  EXPECT_TRUE(settings().UpdateFromCheckinResponse(checkin_response));
 
-  CheckAllSetToDefault();
-  EXPECT_EQ(std::string(), settings().digest());
+  // Only the MCS endpoints were updated:
+  EXPECT_EQ(GURL("https://new.gcm.hostname:5228"),
+            settings().GetMCSMainEndpoint());
+  EXPECT_EQ(GURL("https://new.gcm.hostname:443"),
+            settings().GetMCSFallbackEndpoint());
+
+  // Other settings still set to default.
+  EXPECT_EQ(base::TimeDelta::FromSeconds(kDefaultCheckinInterval),
+            settings().GetCheckinInterval());
+  EXPECT_EQ(GURL(kDefaultCheckinURL), settings().GetCheckinURL());
+  EXPECT_EQ(GURL(kDefaultRegistrationURL), settings().GetRegistrationURL());
+
+  EXPECT_EQ(GServicesSettings::CalculateDigest(new_settings),
+            settings().digest());
 }
 
-// Verifies that no update is done, when a checkin response digest is the same.
-TEST_F(GServicesSettingsTest, UpdateFromCheckinResponseSameDigest) {
-  GCMStore::LoadResult load_result;
-  load_result.gservices_digest = "old_digest";
-  load_result.gservices_settings = alternative_settings();
-  settings().UpdateFromLoadResult(load_result);
+// Verifies that default MCS secure port can be selectively overwritten.
+TEST_F(GServicesSettingsTest, CheckinResponseUpdateMCSSecurePort) {
+  checkin_proto::AndroidCheckinResponse checkin_response;
+  GServicesSettings::SettingsMap new_settings;
+  new_settings["gcm_secure_port"] = "5229";
+  AddSettingsToResponse(checkin_response, new_settings, false);
+
+  EXPECT_TRUE(settings().UpdateFromCheckinResponse(checkin_response));
+
+  // Only the main MCS endpoint was updated:
+  EXPECT_EQ(GURL("https://mtalk.google.com:5229"),
+            settings().GetMCSMainEndpoint());
 
+  // Other settings still set to default.
+  EXPECT_EQ(base::TimeDelta::FromSeconds(kDefaultCheckinInterval),
+            settings().GetCheckinInterval());
+  EXPECT_EQ(GURL(kDefaultCheckinURL), settings().GetCheckinURL());
+  EXPECT_EQ(GURL("https://mtalk.google.com:443"),
+            settings().GetMCSFallbackEndpoint());
+  EXPECT_EQ(GURL(kDefaultRegistrationURL), settings().GetRegistrationURL());
+
+  EXPECT_EQ(GServicesSettings::CalculateDigest(new_settings),
+            settings().digest());
+}
+
+// Update from checkin response should also do incremental update for both cases
+// where some settings are removed or added.
+TEST_F(GServicesSettingsTest, UpdateFromCheckinResponseSettingsDiff) {
   checkin_proto::AndroidCheckinResponse checkin_response;
-  checkin_response.set_digest("old_digest");
-  SetWithAlternativeSettings(checkin_response);
-  EXPECT_FALSE(settings().UpdateFromCheckinResponse(checkin_response));
 
-  CheckAllSetToAlternative();
-  EXPECT_EQ("old_digest", settings().digest());
+  // Only the new settings will be included in the response with settings diff.
+  GServicesSettings::SettingsMap settings_diff;
+  settings_diff["new_setting_1"] = "new_setting_1_value";
+  settings_diff["new_setting_2"] = "new_setting_2_value";
+  settings_diff["gcm_secure_port"] = "5229";
+
+  // Full settings are necessary to calculate digest.
+  GServicesSettings::SettingsMap full_settings(settings_diff);
+  std::string digest = GServicesSettings::CalculateDigest(full_settings);
+
+  checkin_response.Clear();
+  AddSettingsToResponse(checkin_response, settings_diff, true);
+  EXPECT_TRUE(settings().UpdateFromCheckinResponse(checkin_response));
+  EXPECT_EQ(full_settings, settings().settings_map());
+  // Default setting overwritten by settings diff.
+  EXPECT_EQ(GURL("https://mtalk.google.com:5229"),
+            settings().GetMCSMainEndpoint());
+
+  // Setting up diff removing some of the values (including default setting).
+  settings_diff.clear();
+  settings_diff["delete_new_setting_1"] = "";
+  settings_diff["delete_gcm_secure_port"] = "";
+  settings_diff["new_setting_3"] = "new_setting_3_value";
+
+  // Updating full settings to calculate digest.
+  full_settings.erase(full_settings.find("new_setting_1"));
+  full_settings.erase(full_settings.find("gcm_secure_port"));
+  full_settings["new_setting_3"] = "new_setting_3_value";
+  digest = GServicesSettings::CalculateDigest(full_settings);
+
+  checkin_response.Clear();
+  AddSettingsToResponse(checkin_response, settings_diff, true);
+  EXPECT_TRUE(settings().UpdateFromCheckinResponse(checkin_response));
+  EXPECT_EQ(full_settings, settings().settings_map());
+  // Default setting back to norm.
+  EXPECT_EQ(GURL("https://mtalk.google.com:5228"),
+            settings().GetMCSMainEndpoint());
 }
 
 }  // namespace gcm
diff --git a/google_apis/gcm/gcm_client_impl.cc b/google_apis/gcm/gcm_client_impl.cc
index 4065d65..3225454 100644
--- a/google_apis/gcm/gcm_client_impl.cc
+++ b/google_apis/gcm/gcm_client_impl.cc
@@ -271,8 +271,8 @@ void GCMClientImpl::OnLoadCompleted(scoped_ptr<GCMStore::LoadResult> result) {
 void GCMClientImpl::InitializeMCSClient(
     scoped_ptr<GCMStore::LoadResult> result) {
   std::vector<GURL> endpoints;
-  endpoints.push_back(gservices_settings_.mcs_main_endpoint());
-  endpoints.push_back(gservices_settings_.mcs_fallback_endpoint());
+  endpoints.push_back(gservices_settings_.GetMCSMainEndpoint());
+  endpoints.push_back(gservices_settings_.GetMCSFallbackEndpoint());
   connection_factory_ = internals_builder_->BuildConnectionFactory(
       endpoints,
       kDefaultBackoffPolicy,
@@ -339,7 +339,7 @@ void GCMClientImpl::StartCheckin() {
                                            account_ids_,
                                            chrome_build_proto_);
   checkin_request_.reset(
-      new CheckinRequest(gservices_settings_.checkin_url(),
+      new CheckinRequest(gservices_settings_.GetCheckinURL(),
                          request_info,
                          kDefaultBackoffPolicy,
                          base::Bind(&GCMClientImpl::OnCheckinCompleted,
@@ -378,7 +378,7 @@ void GCMClientImpl::OnCheckinCompleted(
     // First update G-services settings, as something might have changed.
     if (gservices_settings_.UpdateFromCheckinResponse(checkin_response)) {
       gcm_store_->SetGServicesSettings(
-          gservices_settings_.GetSettingsMap(),
+          gservices_settings_.settings_map(),
           gservices_settings_.digest(),
           base::Bind(&GCMClientImpl::SetGServicesSettingsCallback,
                      weak_ptr_factory_.GetWeakPtr()));
@@ -418,7 +418,7 @@ void GCMClientImpl::SchedulePeriodicCheckin() {
 }
 
 base::TimeDelta GCMClientImpl::GetTimeToNextCheckin() const {
-  return last_checkin_time_ + gservices_settings_.checkin_interval() -
+  return last_checkin_time_ + gservices_settings_.GetCheckinInterval() -
          clock_->Now();
 }
 
@@ -476,7 +476,7 @@ void GCMClientImpl::Register(const std::string& app_id,
   DCHECK_EQ(0u, pending_registration_requests_.count(app_id));
 
   RegistrationRequest* registration_request =
-      new RegistrationRequest(gservices_settings_.registration_url(),
+      new RegistrationRequest(gservices_settings_.GetRegistrationURL(),
                               request_info,
                               kDefaultBackoffPolicy,
                               base::Bind(&GCMClientImpl::OnRegisterCompleted,
@@ -550,16 +550,15 @@ void GCMClientImpl::Unregister(const std::string& app_id) {
       device_checkin_info_.secret,
       app_id);
 
-  UnregistrationRequest* unregistration_request =
-      new UnregistrationRequest(
-          gservices_settings_.registration_url(),
-          request_info,
-          kDefaultBackoffPolicy,
-          base::Bind(&GCMClientImpl::OnUnregisterCompleted,
-                     weak_ptr_factory_.GetWeakPtr(),
-                     app_id),
-          url_request_context_getter_,
-          &recorder_);
+  UnregistrationRequest* unregistration_request = new UnregistrationRequest(
+      gservices_settings_.GetRegistrationURL(),
+      request_info,
+      kDefaultBackoffPolicy,
+      base::Bind(&GCMClientImpl::OnUnregisterCompleted,
+                 weak_ptr_factory_.GetWeakPtr(),
+                 app_id),
+      url_request_context_getter_,
+      &recorder_);
   pending_unregistration_requests_[app_id] = unregistration_request;
   unregistration_request->Start();
 }
diff --git a/google_apis/gcm/gcm_client_impl_unittest.cc b/google_apis/gcm/gcm_client_impl_unittest.cc
index 7fc0e49..6280370 100644
--- a/google_apis/gcm/gcm_client_impl_unittest.cc
+++ b/google_apis/gcm/gcm_client_impl_unittest.cc
@@ -42,7 +42,6 @@ enum LastEvent {
 const uint64 kDeviceAndroidId = 54321;
 const uint64 kDeviceSecurityToken = 12345;
 const int64 kSettingsCheckinInterval = 16 * 60 * 60;
-const char kSettingsDefaultDigest[] = "default_digest";
 const char kAppId[] = "app_id";
 const char kSender[] = "project_id";
 const char kSender2[] = "project_id2";
@@ -389,6 +388,7 @@ void GCMClientImplTest::CompleteCheckin(
       setting->set_name(it->first);
       setting->set_value(it->second);
     }
+    response.set_settings_diff(false);
   }
 
   std::string response_string;
@@ -687,8 +687,6 @@ class GCMClientImplCheckinTest : public GCMClientImplTest {
   virtual ~GCMClientImplCheckinTest();
 
   virtual void SetUp() OVERRIDE;
-
-  std::map<std::string, std::string> GenerateSettings(int64 checkin_interval);
 };
 
 GCMClientImplCheckinTest::GCMClientImplCheckinTest() {
@@ -715,18 +713,20 @@ TEST_F(GCMClientImplCheckinTest, GServicesSettingsAfterInitialCheckin) {
   settings["gcm_hostname"] = "alternative.gcm.host";
   settings["gcm_secure_port"] = "7777";
   settings["gcm_registration_url"] = "http://alternative.url/registration";
-  CompleteCheckin(
-      kDeviceAndroidId, kDeviceSecurityToken, kSettingsDefaultDigest, settings);
+  CompleteCheckin(kDeviceAndroidId,
+                  kDeviceSecurityToken,
+                  GServicesSettings::CalculateDigest(settings),
+                  settings);
   EXPECT_EQ(base::TimeDelta::FromSeconds(kSettingsCheckinInterval),
-            gservices_settings().checkin_interval());
+            gservices_settings().GetCheckinInterval());
   EXPECT_EQ(GURL("http://alternative.url/checkin"),
-            gservices_settings().checkin_url());
+            gservices_settings().GetCheckinURL());
   EXPECT_EQ(GURL("http://alternative.url/registration"),
-            gservices_settings().registration_url());
+            gservices_settings().GetRegistrationURL());
   EXPECT_EQ(GURL("https://alternative.gcm.host:7777"),
-            gservices_settings().mcs_main_endpoint());
+            gservices_settings().GetMCSMainEndpoint());
   EXPECT_EQ(GURL("https://alternative.gcm.host:443"),
-            gservices_settings().mcs_fallback_endpoint());
+            gservices_settings().GetMCSFallbackEndpoint());
 }
 
 // This test only checks that periodic checkin happens.
@@ -737,13 +737,17 @@ TEST_F(GCMClientImplCheckinTest, PeriodicCheckin) {
   settings["gcm_hostname"] = "alternative.gcm.host";
   settings["gcm_secure_port"] = "7777";
   settings["gcm_registration_url"] = "http://alternative.url/registration";
-  CompleteCheckin(
-      kDeviceAndroidId, kDeviceSecurityToken, kSettingsDefaultDigest, settings);
+  CompleteCheckin(kDeviceAndroidId,
+                  kDeviceSecurityToken,
+                  GServicesSettings::CalculateDigest(settings),
+                  settings);
   EXPECT_EQ(2, clock()->call_count());
 
   PumpLoopUntilIdle();
-  CompleteCheckin(
-      kDeviceAndroidId, kDeviceSecurityToken, kSettingsDefaultDigest, settings);
+  CompleteCheckin(kDeviceAndroidId,
+                  kDeviceSecurityToken,
+                  GServicesSettings::CalculateDigest(settings),
+                  settings);
 }
 
 TEST_F(GCMClientImplCheckinTest, LoadGSettingsFromStore) {
@@ -753,22 +757,24 @@ TEST_F(GCMClientImplCheckinTest, LoadGSettingsFromStore) {
   settings["gcm_hostname"] = "alternative.gcm.host";
   settings["gcm_secure_port"] = "7777";
   settings["gcm_registration_url"] = "http://alternative.url/registration";
-  CompleteCheckin(
-      kDeviceAndroidId, kDeviceSecurityToken, kSettingsDefaultDigest, settings);
+  CompleteCheckin(kDeviceAndroidId,
+                  kDeviceSecurityToken,
+                  GServicesSettings::CalculateDigest(settings),
+                  settings);
 
   BuildGCMClient(base::TimeDelta());
   InitializeGCMClient();
 
   EXPECT_EQ(base::TimeDelta::FromSeconds(kSettingsCheckinInterval),
-            gservices_settings().checkin_interval());
+            gservices_settings().GetCheckinInterval());
   EXPECT_EQ(GURL("http://alternative.url/checkin"),
-            gservices_settings().checkin_url());
+            gservices_settings().GetCheckinURL());
   EXPECT_EQ(GURL("http://alternative.url/registration"),
-            gservices_settings().registration_url());
+            gservices_settings().GetRegistrationURL());
   EXPECT_EQ(GURL("https://alternative.gcm.host:7777"),
-            gservices_settings().mcs_main_endpoint());
+            gservices_settings().GetMCSMainEndpoint());
   EXPECT_EQ(GURL("https://alternative.gcm.host:443"),
-            gservices_settings().mcs_fallback_endpoint());
+            gservices_settings().GetMCSFallbackEndpoint());
 }
 
 }  // namespace gcm