Add tests for the Display operation of the mac notification bridge.

chrome/browser/notifications/notification_platform_bridge_mac.mm

Index: chrome/browser/notifications/notification_platform_bridge_mac.mm
diff --git a/chrome/browser/notifications/notification_platform_bridge_mac.mm b/chrome/browser/notifications/notification_platform_bridge_mac.mm
index e96756be9d07f2003944297157bc9d80f3a2cb7c..de66a065d20416e73f08a8443be41cab890888ec 100644
--- a/chrome/browser/notifications/notification_platform_bridge_mac.mm
+++ b/chrome/browser/notifications/notification_platform_bridge_mac.mm
@@ -92,9 +92,18 @@ NotificationPlatformBridge* NotificationPlatformBridge::Create() {
 
 NotificationPlatformBridgeMac::NotificationPlatformBridgeMac(
     NSUserNotificationCenter* notification_center)
+    : NotificationPlatformBridgeMac(notification_center,
+                                    true /* set_delegate */) {}

[Nico, 2016/07/12 17:54:38]

please use /*set_delegate=*/true (the spelling you have is ambiguous for false
parameters: Does `false /*do_it*/` mean that do_it is set to false and that it's
not done, or does it mean that the flag is dont_do_it and since it's false we're
about to do_it)?

[Miguel Garcia, 2016/07/13 14:05:16]

Done.

+
+NotificationPlatformBridgeMac::NotificationPlatformBridgeMac(
+    NSUserNotificationCenter* notification_center,
+    bool set_delegate)
     : delegate_([NotificationCenterDelegate alloc]),
       notification_center_(notification_center) {
-  [notification_center_ setDelegate:delegate_.get()];
+  // OCMock does not support dynamic properties yet.
+  // TODO(miguelg): remove once cbug.com/622753 is resolved.
+  if (set_delegate)
+    [notification_center_ setDelegate:delegate_.get()];
 }
 
 NotificationPlatformBridgeMac::~NotificationPlatformBridgeMac() {