Use skia.mojom.BitmapN32 in Notification mojoms

These bitmaps are safer for transport from untrustworthy sources since
all bitmaps should be in N32 format and the browser can make bad
assumptions as a result.

R=dcheng@chromium.org

Bug: 1144462
Change-Id: If91ff350a6aacd601e848b705ea2e397484cc439
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2579667
Commit-Queue: danakj <danakj@chromium.org>
Commit-Queue: Daniel Cheng <dcheng@chromium.org>
Auto-Submit: danakj <danakj@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#834997}

third_party/blink/public/mojom/notifications/notification.mojom

@@ -112,15 +112,15 @@ struct NotificationData {
 // Structure representing the resources associated with a Web Notification.
 struct NotificationResources {
   // Image contents of the notification. May be empty if no image was specified.
-  skia.mojom.BitmapWithArbitraryBpp? image;
+  skia.mojom.BitmapN32? image;
 
   // Icon to be displayed with the notification.
-  skia.mojom.BitmapWithArbitraryBpp? icon;
+  skia.mojom.BitmapN32? icon;
 
   // Badge representing the website displaying the notification.
-  skia.mojom.BitmapWithArbitraryBpp? badge;
+  skia.mojom.BitmapN32? badge;
 
   // Icons for the actions. The size of |action_icons| must match the size
   // of |actions| in the corresponding NotificationData.
-  array<skia.mojom.BitmapWithArbitraryBpp?>? action_icons;
+  array<skia.mojom.BitmapN32?>? action_icons;
 };