Plumb ViewportMetrics change notifications around the world and back.

mojo/services/view_manager/public/interfaces/view_manager.mojom

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 module mojo;
 
 import "geometry/public/interfaces/geometry.mojom";
 import "input_events/public/interfaces/input_events.mojom";
 import "mojo/public/interfaces/application/service_provider.mojom";
 import "native_viewport/public/interfaces/native_viewport.mojom";
@@ skipping 141 matching lines @@
           handle<message_pipe> window_manager_pipe);
 
   // Invoked when the application embedded at |view| is disconnected.
   OnEmbeddedAppDisconnected(uint32 view);
 
   // Invoked when a view's bounds have changed.
   OnViewBoundsChanged(uint32 view,
                       mojo.Rect old_bounds,
                       mojo.Rect new_bounds);
 
+  // Invoked when the viewport metrics for the view have changed.
+  // Clients are expected to propagate this to the view tree.
+  OnViewViewportMetricsChanged(mojo.ViewportMetrics old_metrics,
+                               mojo.ViewportMetrics new_metrics);
+
   // Invoked when a change is done to the hierarchy. A value of 0 is used to
   // identify a null view. For example, if the old_parent is NULL, 0 is
   // supplied.
   // |views| contains any views that are that the client has not been told
   // about. This is not sent for hierarchy changes of views not known to this
   // client or not attached to the tree.
   OnViewHierarchyChanged(uint32 view,
                          uint32 new_parent,
                          uint32 old_parent,
                          array<ViewData> views);
 
   // Invoked when the order of views within a parent changes.
   OnViewReordered(uint32 view_id,
                   uint32 relative_view_id,
-                  OrderDirection direction);                     
+                  OrderDirection direction);
 
   // Invoked when a view is deleted.
   OnViewDeleted(uint32 view);
 
   // Invoked when the visibility of the specified view changes.
   OnViewVisibilityChanged(uint32 view, bool visible);
 
   // Invoked when a change to the visibility of |view| or one if it's ancestors
   // is done such that the drawn state changes. This is only invoked for the
   // top most view of a particular connection. For example, if you have the
   // hierarchy: A -> B1 -> B2 (B2 is a child of B1 and B1 a child of A), B1/B2
   // are from connection 2 and A from connection 1 with all views visible and
   // drawn and the visiblity of A changes to false, then connection 2 is told
   // the drawn state of B1 has changed (to false), but is not told anything
   // about B2 as it's drawn state can be calculated from that of B1.
   //
   // NOTE: This is not invoked if OnViewVisibilityChanged() is invoked.
   OnViewDrawnStateChanged(uint32 view, bool drawn);
 
   // Invoked when a view property is changed. If this change is a removal,
   // |new_data| is null.
   OnViewSharedPropertyChanged(uint32 view, string name, array<uint8>? new_data);
 
   // Invoked when an event is targeted at the specified view.
   OnViewInputEvent(uint32 view, mojo.Event event) => ();
 };