aura-mus: add a drag representation image.

services/ui/ws/window_tree.cc

Index: services/ui/ws/window_tree.cc
diff --git a/services/ui/ws/window_tree.cc b/services/ui/ws/window_tree.cc
index df00978bf891c44a37fc702eb7283ed09e4a30be..7ac04189dc15966ed68054cfc82ba002f51c2ae8 100644
--- a/services/ui/ws/window_tree.cc
+++ b/services/ui/ws/window_tree.cc
@@ -78,7 +78,8 @@ WindowTree::WindowTree(WindowServer* window_server,
       next_window_id_(1),
       access_policy_(std::move(access_policy)),
       event_ack_id_(0),
-      window_manager_internal_(nullptr) {
+      window_manager_internal_(nullptr),
+      weak_factory_(this) {
   if (root)
     roots_.insert(root);
   access_policy_->Init(id_, this);
@@ -233,6 +234,15 @@ void WindowTree::NotifyChangeCompleted(
       change_id, error_code == mojom::WindowManagerErrorCode::SUCCESS);
 }
 
+void WindowTree::OnWmMoveDragImageCompleted() {
+  waiting_for_move_drag_ack_ = false;
+
+  if (has_queued_drag_window_move_) {
+    has_queued_drag_window_move_ = false;
+    OnDragContinued(queued_cursor_location_);
+  }
+}
+
 bool WindowTree::SetCapture(const ClientWindowId& client_window_id) {
   ServerWindow* window = GetWindowByClientId(client_window_id);
   WindowManagerDisplayRoot* display_root = GetWindowManagerDisplayRoot(window);
@@ -1790,8 +1800,15 @@ void WindowTree::GetCursorLocationMemory(
 void WindowTree::PerformDragDrop(
     uint32_t change_id,
     Id source_window_id,
+    const gfx::Point& screen_location,
     const std::unordered_map<std::string, std::vector<uint8_t>>& drag_data,
-    uint32_t drag_operation) {
+    const SkBitmap& drag_image,
+    const gfx::Vector2d& drag_image_offset,
+    uint32_t drag_operation,
+    ui::mojom::DragEventSource source) {
+  // TODO(erg): SkBitmap is the wrong data type for the drag image; we should
+  // be passing ImageSkias once http://crbug.com/655874 is implemented.
+
   ServerWindow* window = GetWindowByClientId(ClientWindowId(source_window_id));
   bool success = window && access_policy_->CanInitiateDragLoop(window);
   if (!success || !ShouldRouteToWindowManager(window)) {
@@ -1821,13 +1838,15 @@ void WindowTree::PerformDragDrop(
     return;
   }
 
-  // TODO(erg): Dealing with |drag_representation| is hard, so we're going to
-  // deal with that later.
+  WindowManagerState* wms = display_root->window_manager_state();
+
+  // Send the drag representation to the window manager.
+  wms->window_tree()->window_manager_internal_->WmBuildDragImage(
+      screen_location, drag_image, drag_image_offset, source);
 
   // Here, we need to dramatically change how the mouse pointer works. Once
   // we've started a drag drop operation, cursor events don't go to windows as
   // normal.
-  WindowManagerState* wms = display_root->window_manager_state();
   window_server_->StartDragLoop(change_id, window, this);
   wms->SetDragDropSourceWindow(this, window, this, drag_data, drag_operation);
 }
@@ -2120,6 +2139,29 @@ bool WindowTree::IsWindowCreatedByWindowManager(
          window->id().client_id;
 }
 
+void WindowTree::OnDragContinued(const gfx::Point& location) {
+  DCHECK(window_server_->in_drag_loop());
+
+  if (window_server_->GetCurrentDragLoopInitiator() != this)

[sky, 2017/03/23 00:05:36]

Remind me when this can ever be false? I'm wondering if it should be a DCHECK?

+    return;
+
+  ServerWindow* window = window_server_->GetCurrentDragLoopWindow();
+  WindowManagerDisplayRoot* display_root = GetWindowManagerDisplayRoot(window);
+  if (!display_root)
+    return;
+
+  if (waiting_for_move_drag_ack_) {
+    has_queued_drag_window_move_ = true;
+    queued_cursor_location_ = location;
+  } else {
+    WindowManagerState* wms = display_root->window_manager_state();
+    waiting_for_move_drag_ack_ = true;
+    wms->window_tree()->window_manager_internal_->WmMoveDragImage(
+        location, base::Bind(&WindowTree::OnWmMoveDragImageCompleted,

[sky, 2017/03/23 00:05:36]

Using 'completed' in the name here makes me think the drag is done. How about
OnWmMoveDragImageAck?

[Elliot Glaysher, 2017/03/23 19:58:44]

Done.

+                             weak_factory_.GetWeakPtr()));

[sky, 2017/03/23 00:05:36]

Can you reset weak_factory_ once the drag is complete locally? That way we don't
have the possibility of an ack coming out of order.

[Elliot Glaysher, 2017/03/23 19:58:44]

Done.

+  }
+}
+
 void WindowTree::OnDragCompleted(bool success, uint32_t action_taken) {
   DCHECK(window_server_->in_drag_loop());
 
@@ -2135,6 +2177,7 @@ void WindowTree::OnDragCompleted(bool success, uint32_t action_taken) {
   window_server_->EndDragLoop();
   WindowManagerState* wms = display_root->window_manager_state();
   wms->EndDragDrop();
+  wms->window_tree()->window_manager_internal_->WmDestroyDragImage();
 
   client()->OnPerformDragDropCompleted(change_id, success, action_taken);
 }