chromeos: exposes functions in ash to get window by window service ids

This is useful in single-process-mash to correlate windows.

BUG=756085
TEST=none

Change-Id: I8845b62754ba5c34d352b49491078e69a35719aa
Reviewed-on: https://chromium-review.googlesource.com/c/1323705
Commit-Queue: Scott Violet <sky@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606130}

ash/BUILD.gn

@@ -84,6 +84,7 @@ component("ash") {
     "wm/window_util.h",
     "wm/wm_event.h",
     "wm/workspace/workspace_window_resizer.h",
+    "ws/window_lookup.h",
   ]
   sources = [
     "accelerators/accelerator_commands.cc",
@@ -1248,6 +1249,7 @@ component("ash") {
     "ws/ash_gpu_interface_provider.h",
     "ws/ash_window_manager.cc",
     "ws/ash_window_manager.h",
+    "ws/window_lookup.cc",
     "ws/window_service_delegate_impl.cc",
     "ws/window_service_delegate_impl.h",
     "ws/window_service_owner.cc",

ash/ws/window_lookup.cc

+// Copyright 2018 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 "ash/ws/window_lookup.h"
+
+#include "ash/shell.h"
+#include "ash/ws/window_service_owner.h"
+#include "services/ws/window_service.h"
+
+namespace ash {
+namespace window_lookup {
+
+aura::Window* GetWindowByClientId(ws::Id transport_id) {
+  return Shell::Get()
+      ->window_service_owner()
+      ->window_service()
+      ->GetWindowByClientId(transport_id);
+}
+
+ws::ClientSpecificId GetFirstWindowTreeClientId() {
+  return Shell::Get()
+      ->window_service_owner()
+      ->window_service()
+      ->GetFirstWindowTreeClientId();
+}
+
+}  // namespace window_lookup
+}  // namespace ash

ash/ws/window_lookup.h

+// Copyright 2018 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.
+
+#ifndef ASH_WS_WINDOW_LOOKUP_H_
+#define ASH_WS_WINDOW_LOOKUP_H_
+
+#include "ash/ash_export.h"
+#include "services/ws/common/types.h"
+
+namespace aura {
+class Window;
+}
+
+// TODO: this file is only necessary for single-process mash and should be
+// removed.
+namespace ash {
+namespace window_lookup {
+
+// Returns the aura::Window by transport id.
+ASH_EXPORT aura::Window* GetWindowByClientId(ws::Id transport_id);
+
+// Returns the id of the first WindowTreeClient. That is, the id assigned to
+// the first client that connects to the WindowService.
+ASH_EXPORT ws::ClientSpecificId GetFirstWindowTreeClientId();
+
+}  // namespace window_lookup
+}  // namespace ash
+
+#endif  // ASH_WS_WINDOW_LOOKUP_H_

services/ws/window_service.cc

@@ -10,6 +10,7 @@
 #include "mojo/public/cpp/bindings/strong_binding.h"
 #include "services/service_manager/public/cpp/bind_source_info.h"
 #include "services/ws/common/switches.h"
+#include "services/ws/common/util.h"
 #include "services/ws/embedding.h"
 #include "services/ws/event_injector.h"
 #include "services/ws/event_queue.h"
@@ -78,6 +79,10 @@ WindowService::~WindowService() {
   DCHECK(window_trees_.empty());
 }
 
+ClientSpecificId WindowService::GetFirstWindowTreeClientId() const {
+  return decrement_client_ids_ ? kInitialClientIdDecrement : kInitialClientId;
+}
+
 ServerWindow* WindowService::GetServerWindowForWindowCreateIfNecessary(
     aura::Window* window) {
   ServerWindow* server_window = ServerWindow::GetMayBeNull(window);
@@ -126,6 +131,13 @@ bool WindowService::IsTopLevelWindow(const aura::Window* window) {
   return server_window && server_window->IsTopLevel();
 }
 
+aura::Window* WindowService::GetWindowByClientId(Id transport_id) {
+  const ClientSpecificId client_id = ClientIdFromTransportId(transport_id);
+  WindowTree* window_tree = GetTreeById(client_id);
+  return window_tree ? window_tree->GetWindowByTransportId(transport_id)
+                     : nullptr;
+}
+
 WindowService::TreeAndWindowId
 WindowService::FindTreeWithScheduleEmbedForExistingClient(
     const base::UnguessableToken& embed_token) {
@@ -272,6 +284,14 @@ void WindowService::OnBindInterface(
   }
 }
 
+WindowTree* WindowService::GetTreeById(ClientSpecificId id) {
+  for (WindowTree* tree : window_trees_) {
+    if (tree->client_id() == id)
+      return tree;
+  }
+  return nullptr;
+}
+
 void WindowService::SetSurfaceActivationCallback(
     base::OnceCallback<void(const std::string&)> callback) {
   // Surface activation callbacks are expensive, and allowed only in tests.

services/ws/window_service.h

@@ -87,6 +87,9 @@ class COMPONENT_EXPORT(WINDOW_SERVICE) WindowService
                 aura::Env* env = nullptr);
   ~WindowService() override;
 
+  // Returns the id of the first WindowTreeClient.
+  ClientSpecificId GetFirstWindowTreeClientId() const;
+
   // Gets the ServerWindow for |window|, creating if necessary.
   ServerWindow* GetServerWindowForWindowCreateIfNecessary(aura::Window* window);
 
@@ -110,6 +113,9 @@ class COMPONENT_EXPORT(WINDOW_SERVICE) WindowService
   // Returns true if |window| hosts a remote client and is a toplevel window.
   static bool IsTopLevelWindow(const aura::Window* window);
 
+  // Returns the window representing the specified id.
+  aura::Window* GetWindowByClientId(Id transport_id);
+
   struct TreeAndWindowId {
     ClientWindowId id;
     WindowTree* tree = nullptr;
@@ -190,6 +196,8 @@ class COMPONENT_EXPORT(WINDOW_SERVICE) WindowService
   friend class WindowServerTestImpl;
   friend class WindowServiceTestHelper;
 
+  WindowTree* GetTreeById(ClientSpecificId id);
+
   // Sets a callback to be called whenever a surface is activated. This
   // corresponds to a client submitting a new CompositorFrame for a Window. This
   // should only be called in a test configuration.