mus: Use the new drag API to implement tab dragging in chrome.

ash/mus/window_manager.cc

Index: ash/mus/window_manager.cc
diff --git a/ash/mus/window_manager.cc b/ash/mus/window_manager.cc
index bd483355aead76a4d9748308f4119ac8c2708f31..933fef86a9209e2383e4a1522a7e21b6c277a3a4 100644
--- a/ash/mus/window_manager.cc
+++ b/ash/mus/window_manager.cc
@@ -12,6 +12,7 @@
 #include "ash/mus/bridge/wm_lookup_mus.h"
 #include "ash/mus/bridge/wm_shell_mus.h"
 #include "ash/mus/bridge/wm_window_mus.h"
+#include "ash/mus/frame/move_event_handler.h"
 #include "ash/mus/non_client_frame_controller.h"
 #include "ash/mus/property_util.h"
 #include "ash/mus/root_window_controller.h"
@@ -27,6 +28,7 @@
 #include "components/mus/public/cpp/window_tree_client.h"
 #include "components/mus/public/interfaces/mus_constants.mojom.h"
 #include "components/mus/public/interfaces/window_manager.mojom.h"
+#include "ui/base/hit_test.h"
 #include "ui/events/mojo/event.mojom.h"
 #include "ui/views/mus/screen_mus.h"
 
@@ -229,6 +231,28 @@ void WindowManager::OnWmNewDisplay(::mus::Window* window,
   CreateRootWindowController(window, display);
 }
 
+void WindowManager::OnWmPerformMoveLoop(uint32_t change_id,
+                                        uint32_t window_id,
+                                        const gfx::Point& cursor_location) {
+  WmWindowMus* child_window =
+      WmWindowMus::Get(window_tree_client_->GetWindowByServerId(window_id));
+  MoveEventHandler* handler = MoveEventHandler::GetForWindow(child_window);
+  handler->AttemptToStartDrag(cursor_location, HTCAPTION,
+                              base::Bind(&WindowManager::OnWmMoveLoopCompleted,
+                                         base::Unretained(this), change_id));
+}
+
+void WindowManager::OnWmCancelMoveLoop(uint32_t window_id) {
+  WmWindowMus* child_window =
+      WmWindowMus::Get(window_tree_client_->GetWindowByServerId(window_id));
+  MoveEventHandler* handler = MoveEventHandler::GetForWindow(child_window);
+  handler->RevertDrag();
+}
+
+void WindowManager::OnWmMoveLoopCompleted(uint32_t change_id, bool succeeded) {
+  window_manager_client_->OnWmMoveLoopCompleted(change_id, succeeded);
+}
+
 void WindowManager::OnAccelerator(uint32_t id, const ui::Event& event) {
   switch (id) {
     case kWindowSwitchAccelerator:
@@ -240,15 +264,5 @@ void WindowManager::OnAccelerator(uint32_t id, const ui::Event& event) {
   }
 }
 
-void WindowManager::OnWmPerformMoveLoop(uint32_t change_id,
-                                        uint32_t window_id,
-                                        const gfx::Point& cursor_location) {
-  NOTIMPLEMENTED();
-}
-
-void WindowManager::OnWmCancelMoveLoop(uint32_t window_id) {
-  NOTIMPLEMENTED();
-}
-
 }  // namespace mus
 }  // namespace ash