mus: Add EventObserver to allow passively listening to UI events

components/mus/ws/window_tree.cc

 // 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.
 
 #include "components/mus/ws/window_tree.h"
 
 #include <stddef.h>
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/stl_util.h"
 #include "components/mus/ws/default_access_policy.h"
 #include "components/mus/ws/display.h"
 #include "components/mus/ws/display_manager.h"
+#include "components/mus/ws/event_matcher.h"
 #include "components/mus/ws/focus_controller.h"
 #include "components/mus/ws/operation.h"
 #include "components/mus/ws/platform_display.h"
 #include "components/mus/ws/server_window.h"
 #include "components/mus/ws/server_window_observer.h"
 #include "components/mus/ws/window_manager_state.h"
 #include "components/mus/ws/window_server.h"
 #include "components/mus/ws/window_tree_binding.h"
 #include "mojo/converters/geometry/geometry_type_converters.h"
 #include "mojo/converters/ime/ime_type_converters.h"
@@ skipping 919 matching lines @@
                                         const ui::Event& event) {
   DCHECK(!event_ack_id_);
   // We do not want to create a sequential id for each event, because that can
   // leak some information to the client. So instead, manufacture the id
   // randomly.
   // TODO(moshayedi): Find a faster way to generate ids.
   event_ack_id_ = 0x1000000 | (rand() & 0xffffff);
   event_source_wms_ = GetWindowManagerState(target);
   // Should only get events from windows attached to a host.
   DCHECK(event_source_wms_);
-  client()->OnWindowInputEvent(event_ack_id_,
-                               ClientWindowIdForWindow(target).id,
-                               mojom::Event::From(event));
+  bool matched_observer =
+      event_observer_matcher_ && event_observer_matcher_->MatchesEvent(event);
+  client()->OnWindowInputEvent(
+      event_ack_id_, ClientWindowIdForWindow(target).id,
+      mojom::Event::From(event), matched_observer ? event_observer_id_ : 0);
+}
+
+void WindowTree::SendToEventObserver(const ui::Event& event) {
+  if (event_observer_matcher_ && event_observer_matcher_->MatchesEvent(event))
+    client()->OnEventObserved(mojom::Event::From(event), event_observer_id_);
 }
 
 void WindowTree::NewWindow(
     uint32_t change_id,
     Id transport_window_id,
     mojo::Map<mojo::String, mojo::Array<uint8_t>> transport_properties) {
   std::map<std::string, std::vector<uint8_t>> properties;
   if (!transport_properties.is_null()) {
     properties =
         transport_properties.To<std::map<std::string, std::vector<uint8_t>>>();
@@ skipping 135 matching lines @@
                  (!current_capture_window ||
                   access_policy_->CanSetCapture(current_capture_window)) &&
                  window == current_capture_window;
   if (success) {
     Operation op(this, window_server_, OperationType::RELEASE_CAPTURE);
     success = wms->SetCapture(nullptr, false);
   }
   client()->OnChangeCompleted(change_id, success);
 }
 
+void WindowTree::SetEventObserver(mojom::EventMatcherPtr matcher,
+                                  uint32_t observer_id) {
+  if (!matcher.is_null() && observer_id != 0) {
+    event_observer_matcher_.reset(new EventMatcher(*matcher));
+    event_observer_id_ = observer_id;
+  } else {
+    event_observer_matcher_.reset();
+    event_observer_id_ = 0;
+  }
+}
+
 void WindowTree::SetWindowBounds(uint32_t change_id,
                                  Id window_id,
                                  mojo::RectPtr bounds) {
   ServerWindow* window = GetWindowByClientId(ClientWindowId(window_id));
   if (window && ShouldRouteToWindowManager(window)) {
     const uint32_t wm_change_id =
         window_server_->GenerateWindowManagerChangeId(this, change_id);
     // |window_id| may be a client id, use the id from the window to ensure
     // the windowmanager doesn't get an id it doesn't know about.
     WindowManagerState* wms = display_manager()
@@ skipping 287 matching lines @@
 }
 
 bool WindowTree::IsWindowRootOfAnotherTreeForAccessPolicy(
     const ServerWindow* window) const {
   WindowTree* tree = window_server_->GetTreeWithRoot(window);
   return tree && tree != this;
 }
 
 }  // namespace ws
 }  // namespace mus