Initial implementation of new-style notification

ui/message_center/views/message_view_factory.cc

Index: ui/message_center/views/message_view_factory.cc
diff --git a/ui/message_center/views/message_view_factory.cc b/ui/message_center/views/message_view_factory.cc
index df5f6d923f7e8b9a8b313a6504974aa19d0beeeb..d554111422ebc1dd62e945439e1a0de851e7d9d1 100644
--- a/ui/message_center/views/message_view_factory.cc
+++ b/ui/message_center/views/message_view_factory.cc
@@ -4,20 +4,40 @@
 
 #include "ui/message_center/views/message_view_factory.h"
 
+#include "base/command_line.h"
+#include "ui/message_center/message_center_switches.h"
 #include "ui/message_center/notification_types.h"
 #include "ui/message_center/views/custom_notification_view.h"
 #include "ui/message_center/views/notification_view.h"
+#include "ui/message_center/views/notification_view_md.h"
 
 #if defined(OS_WIN)
 #include "ui/base/win/shell.h"
 #endif
 
+namespace {
+static base::Optional<bool> new_style_notification_enabled;

[fukino, 2017/05/25 07:35:10]

This seems to be forbidden by coding style.
https://google.github.io/styleguide/cppguide.html#Static_and_Global_Variables

I think we don't need to worry about the cost of
base::CommandLine::ForCurrentProcess()->GetSwitchValuesASCII() or HasSwitch()
and we can check the flag each time the MessageView is constructed.
If we measure the performance overhead about it, let's optimize it later.

[yoshiki, 2017/05/29 03:52:38]

Ok, Done.

+}  // anonymous namespace
+
 namespace message_center {
 
 // static
 MessageView* MessageViewFactory::Create(MessageCenterController* controller,
                                         const Notification& notification,
                                         bool top_level) {
+  // One-time lazy initialization of |new_style_notification_enabled|.
+  if (!new_style_notification_enabled) {
+    new_style_notification_enabled = false;  // default value
+    std::string arg =
+        base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
+            switches::kMessageCenterNewStyleNotification);
+    if (arg == switches::kMessageCenterNewStyleNotificationEnabled) {
+      new_style_notification_enabled = true;
+    } else if (arg == switches::kMessageCenterNewStyleNotificationDisabled) {
+      new_style_notification_enabled = false;
+    }
+  }
+
   MessageView* notification_view = nullptr;
   switch (notification.type()) {
     case NOTIFICATION_TYPE_BASE_FORMAT:
@@ -26,7 +46,10 @@ MessageView* MessageViewFactory::Create(MessageCenterController* controller,
     case NOTIFICATION_TYPE_SIMPLE:
     case NOTIFICATION_TYPE_PROGRESS:
       // All above roads lead to the generic NotificationView.
-      notification_view = new NotificationView(controller, notification);
+      if (*new_style_notification_enabled)
+        notification_view = new NotificationViewMD(controller, notification);
+      else
+        notification_view = new NotificationView(controller, notification);
       break;
     case NOTIFICATION_TYPE_CUSTOM:
       notification_view = new CustomNotificationView(controller, notification);