Add Tether to list of ash system notifiers.

Without being a system notifier, 
MultiUserNotificationBlockerChromeOS::ShouldShowNotification()
returns false, preventing Tether notifications from
displaying. It's appropriate to consider Tether a system 
notifier given that it is baked into the system tray and 
Settings.

Bug: 747639, 672263
Change-Id: I0f0d9a4ce3da7c62b148af979c611eaca6682053
Reviewed-on: https://chromium-review.googlesource.com/596833
Commit-Queue: Ryan Hansberry <hansberry@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491416}

ash/system/system_notifier.cc

@@ -32,7 +32,8 @@ const char* kAshSystemNotifiers[] = {
     kNotifierDisk, kNotifierLocale, kNotifierMultiProfileFirstRun,
     kNotifierNetwork, kNotifierNetworkPortalDetector, kNotifierScreenshot,
     kNotifierScreenCapture, kNotifierScreenShare, kNotifierSessionLengthTimeout,
-    kNotifierSms, kNotifierSupervisedUser, kNotifierWebUsb, kNotifierWifiToggle,
+    kNotifierSms, kNotifierSupervisedUser, kNotifierTether, kNotifierWebUsb,
+    kNotifierWifiToggle,
     // Note: Order doesn't matter here, so keep this in alphabetic order, don't
     // just add your stuff at the end!
     NULL};
@@ -76,6 +77,7 @@ const char kNotifierScreenShare[] = "ash.screen-share";
 const char kNotifierSessionLengthTimeout[] = "ash.session-length-timeout";
 const char kNotifierSms[] = "ash.sms";
 const char kNotifierSupervisedUser[] = "ash.locally-managed-user";
+const char kNotifierTether[] = "ash.tether";
 const char kNotifierWebUsb[] = "ash.webusb";
 const char kNotifierWifiToggle[] = "ash.wifi-toggle";
 

ash/system/system_notifier.h

@@ -39,6 +39,7 @@ ASH_EXPORT extern const char kNotifierScreenShare[];
 ASH_EXPORT extern const char kNotifierSessionLengthTimeout[];
 ASH_EXPORT extern const char kNotifierSms[];
 ASH_EXPORT extern const char kNotifierSupervisedUser[];
+ASH_EXPORT extern const char kNotifierTether[];
 ASH_EXPORT extern const char kNotifierWebUsb[];
 ASH_EXPORT extern const char kNotifierWifiToggle[];
 

chrome/browser/chromeos/net/DEPS

@@ -17,4 +17,7 @@ specific_include_rules = {
     "+ash/system/system_notifier.h",
     "+ash/resources/grit/ash_resources.h",
   ],
+  "tether_notification_presenter\.cc": [
+    "+ash/system/system_notifier.h",
+  ],
 }

chrome/browser/chromeos/net/tether_notification_presenter.cc

@@ -4,6 +4,7 @@
 
 #include "chrome/browser/chromeos/net/tether_notification_presenter.h"
 
+#include "ash/system/system_notifier.h"
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/string16.h"
@@ -54,11 +55,39 @@ int GetNormalizedSignalStrength(int signal_strength) {
   return std::min(std::max(normalized_signal_strength, 0), 4);
 }
 
-}  // namespace
+std::unique_ptr<message_center::Notification> CreateNotification(
+    const std::string& id,
+    const base::string16& title,
+    const base::string16& message,
+    const message_center::RichNotificationData rich_notification_data,
+    int signal_strength) {
+  auto source = base::MakeUnique<ash::network_icon::SignalStrengthImageSource>(
+      ash::network_icon::BARS, gfx::kGoogleBlue500, kTetherSignalIconSize,
+      GetNormalizedSignalStrength(signal_strength));
+  std::unique_ptr<message_center::Notification> notification =
+      base::MakeUnique<message_center::Notification>(
+          message_center::NotificationType::NOTIFICATION_TYPE_SIMPLE, id, title,
+          message,
+          gfx::Image(gfx::ImageSkia(std::move(source), kTetherSignalIconSize)),
+          base::string16() /* display_source */, GURL() /* origin_url */,
+          message_center::NotifierId(
+              message_center::NotifierId::NotifierType::SYSTEM_COMPONENT,
+              ash::system_notifier::kNotifierTether),
+          rich_notification_data, nullptr);
+  notification->SetSystemPriority();
+  return notification;
+}
 
-// static
-constexpr const char TetherNotificationPresenter::kTetherNotifierId[] =
-    "cros_tether_notification_ids.notifier_id";
+std::unique_ptr<message_center::Notification>
+CreateNotificationWithMediumSignalStrengthIcon(const std::string& id,
+                                               const base::string16& title,
+                                               const base::string16& message) {
+  return CreateNotification(id, title, message,
+                            message_center::RichNotificationData(),
+                            kMediumSignalStrength);
+}
+
+}  // namespace
 
 // static
 constexpr const char TetherNotificationPresenter::kActiveHostNotificationId[] =
@@ -82,44 +111,10 @@ constexpr const char
 // static
 constexpr const char* const
     TetherNotificationPresenter::kIdsWhichOpenTetherSettingsOnClick[] = {
-        TetherNotificationPresenter::kTetherNotifierId,
         TetherNotificationPresenter::kActiveHostNotificationId,
         TetherNotificationPresenter::kPotentialHotspotNotificationId,
         TetherNotificationPresenter::kSetupRequiredNotificationId};
 
-// static
-std::unique_ptr<message_center::Notification>
-TetherNotificationPresenter::CreateNotificationWithMediumSignalStrengthIcon(
-    const std::string& id,
-    const base::string16& title,
-    const base::string16& message) {
-  return CreateNotification(id, title, message,
-                            message_center::RichNotificationData(),
-                            kMediumSignalStrength);
-}
-
-// static
-std::unique_ptr<message_center::Notification>
-TetherNotificationPresenter::CreateNotification(
-    const std::string& id,
-    const base::string16& title,
-    const base::string16& message,
-    const message_center::RichNotificationData rich_notification_data,
-    int signal_strength) {
-  auto source = base::MakeUnique<ash::network_icon::SignalStrengthImageSource>(
-      ash::network_icon::BARS, gfx::kGoogleBlue500, kTetherSignalIconSize,
-      GetNormalizedSignalStrength(signal_strength));
-  return base::MakeUnique<message_center::Notification>(
-      message_center::NotificationType::NOTIFICATION_TYPE_SIMPLE, id, title,
-      message,
-      gfx::Image(gfx::ImageSkia(std::move(source), kTetherSignalIconSize)),
-      base::string16() /* display_source */, GURL() /* origin_url */,
-      message_center::NotifierId(
-          message_center::NotifierId::NotifierType::SYSTEM_COMPONENT,
-          kTetherNotifierId),
-      rich_notification_data, nullptr);
-}
-
 TetherNotificationPresenter::TetherNotificationPresenter(
     Profile* profile,
     message_center::MessageCenter* message_center,

chrome/browser/chromeos/net/tether_notification_presenter.h

@@ -73,8 +73,9 @@ class TetherNotificationPresenter
   };
 
  private:
+  friend class TetherNotificationPresenterTest;
+
   // IDs associated with Tether notification types.
-  static const char kTetherNotifierId[];
   static const char kPotentialHotspotNotificationId[];
   static const char kActiveHostNotificationId[];
   static const char kSetupRequiredNotificationId[];
@@ -83,19 +84,6 @@ class TetherNotificationPresenter
   // IDs of all notifications which, when clicked, open mobile data settings.
   static const char* const kIdsWhichOpenTetherSettingsOnClick[];
 
-  static std::unique_ptr<message_center::Notification>
-  CreateNotificationWithMediumSignalStrengthIcon(const std::string& id,
-                                                 const base::string16& title,
-                                                 const base::string16& message);
-  static std::unique_ptr<message_center::Notification> CreateNotification(
-      const std::string& id,
-      const base::string16& title,
-      const base::string16& message,
-      const message_center::RichNotificationData rich_notification_data,
-      int signal_strength);
-
-  friend class TetherNotificationPresenterTest;
-
   void SetSettingsUiDelegateForTesting(
       std::unique_ptr<SettingsUiDelegate> settings_ui_delegate);
   void ShowNotification(