[Ash] Add --suppress-message-center-popups.

This hides all notification popups. Its only purpose is for making sure
popups don't interfere with automated tests.

Bug: 807101
Change-Id: I7776af1b0fbd795ed1899a78fa5a7aef1c7b6f9a
Reviewed-on: https://chromium-review.googlesource.com/894152
Commit-Queue: Evan Stade <estade@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533736}

ash/message_center/message_center_controller.cc

@@ -4,6 +4,8 @@
 
 #include "ash/message_center/message_center_controller.h"
 
+#include "ash/public/cpp/ash_switches.h"
+#include "base/command_line.h"
 #include "ui/message_center/message_center.h"
 #include "ui/message_center/public/cpp/notification_delegate.h"
 #include "ui/message_center/public/cpp/notifier_id.h"
@@ -15,6 +17,23 @@ namespace ash {
 
 namespace {
 
+// A notification blocker that unconditionally blocks toasts. Implements
+// --suppress-message-center-notifications.
+class PopupNotificationBlocker : public message_center::NotificationBlocker {
+ public:
+  PopupNotificationBlocker(MessageCenter* message_center)
+      : NotificationBlocker(message_center) {}
+  ~PopupNotificationBlocker() override = default;
+
+  bool ShouldShowNotificationAsPopup(
+      const message_center::Notification& notification) const override {
+    return false;
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(PopupNotificationBlocker);
+};
+
 // This notification delegate passes actions back to the client that asked for
 // the notification (Chrome).
 class AshClientNotificationDelegate
@@ -51,7 +70,13 @@ MessageCenterController::MessageCenterController()
     : fullscreen_notification_blocker_(MessageCenter::Get()),
       inactive_user_notification_blocker_(MessageCenter::Get()),
       session_state_notification_blocker_(MessageCenter::Get()),
-      binding_(this) {}
+      binding_(this) {
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kSuppressMessageCenterPopups)) {
+    all_popup_blocker_ =
+        std::make_unique<PopupNotificationBlocker>(MessageCenter::Get());
+  }
+}
 
 MessageCenterController::~MessageCenterController() = default;
 

ash/message_center/message_center_controller.h

@@ -74,6 +74,7 @@ class ASH_EXPORT MessageCenterController
   FullscreenNotificationBlocker fullscreen_notification_blocker_;
   InactiveUserNotificationBlocker inactive_user_notification_blocker_;
   SessionStateNotificationBlocker session_state_notification_blocker_;
+  std::unique_ptr<message_center::NotificationBlocker> all_popup_blocker_;
 
   NotifierSettingsListener* notifier_id_ = nullptr;
 

ash/public/cpp/ash_switches.cc

@@ -184,6 +184,9 @@ const char kShowWebUiLock[] = "show-webui-lock";
 const char kTouchscreenUsableWhileScreenOff[] =
     "touchscreen-usable-while-screen-off";
 
+// Hides all Message Center notification popups (toasts). Used for testing.
+const char kSuppressMessageCenterPopups[] = "suppress-message-center-popups";
+
 // By default we use classic IME (i.e. InputMethodChromeOS) in kMus. This flag
 // enables the IME service (i.e. InputMethodMus) instead.
 const char kUseIMEService[] = "use-ime-service";

ash/public/cpp/ash_switches.h

@@ -66,6 +66,7 @@ ASH_PUBLIC_EXPORT extern const char kShowPowerButtonMenu[];
 ASH_PUBLIC_EXPORT extern const char kShowTaps[];
 ASH_PUBLIC_EXPORT extern const char kShowViewsLogin[];
 ASH_PUBLIC_EXPORT extern const char kShowWebUiLock[];
+ASH_PUBLIC_EXPORT extern const char kSuppressMessageCenterPopups[];
 ASH_PUBLIC_EXPORT extern const char kTouchscreenUsableWhileScreenOff[];
 ASH_PUBLIC_EXPORT extern const char kUseIMEService[];