aura-mus: add a drag representation image.

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 02101212c93ed96acdc252c4145d7ca2aff8bfff..6229e5f5211b8bfffacc89d2c5bdae9fc496ed5a 100644
--- a/ash/mus/window_manager.cc
+++ b/ash/mus/window_manager.cc
@@ -8,6 +8,7 @@
 
 #include <utility>
 
+#include "ash/common/drag_drop/drag_image_view.h"
 #include "ash/common/session/session_controller.h"
 #include "ash/common/wm/container_finder.h"
 #include "ash/common/wm/window_state.h"
@@ -366,6 +367,48 @@ void WindowManager::OnWmClientJankinessChanged(
     window->SetProperty(kWindowIsJanky, janky);
 }
 
+void WindowManager::OnWmBuildDragImage(
+    const gfx::Point& location_in_screen_coordinates,
+    const SkBitmap& drag_image,
+    const gfx::Vector2d& drag_image_offset,
+    ui::mojom::DragEventSource source) {
+  if (drag_image.isNull())
+    return;
+
+  // TODO(erg): Get the right display for this drag image. Right now, none of
+  // the drag drop code is multidisplay aware.
+
+  // TODO(erg): SkBitmap is the wrong data type for the drag image; we should
+  // be passing ImageSkias once http://crbug.com/655874 is implemented.
+
+  WmWindow* root_window =
+      WmWindow::Get((*GetRootWindowControllers().begin())->GetRootWindow());
+
+  ui::DragDropTypes::DragEventSource ui_source =
+      source == ui::mojom::DragEventSource::MOUSE
+          ? ui::DragDropTypes::DRAG_EVENT_SOURCE_MOUSE
+          : ui::DragDropTypes::DRAG_EVENT_SOURCE_TOUCH;
+  drag_image_.reset(new DragImageView(root_window, ui_source));

[sky, 2017/03/23 00:05:35]

MakeUnique.

[Elliot Glaysher, 2017/03/23 19:58:43]

Done.

+  drag_image_->SetImage(gfx::ImageSkia::CreateFrom1xBitmap(drag_image));
+  gfx::Size size = drag_image_->GetPreferredSize();
+  gfx::Rect drag_image_bounds(
+      location_in_screen_coordinates - drag_image_offset, size);
+  drag_image_->SetBoundsInScreen(drag_image_bounds);
+  drag_image_->SetWidgetVisible(true);
+
+  drag_image_offset_ = drag_image_offset;
+}
+
+void WindowManager::OnWmMoveDragImage(const gfx::Point& cursor_location) {
+  if (drag_image_)
+    drag_image_->SetScreenPosition(cursor_location - drag_image_offset_);
+}
+
+void WindowManager::OnWmDestroyDragImage() {
+  drag_image_.reset();
+  drag_image_offset_ = gfx::Vector2d(0, 0);
+}
+
 void WindowManager::OnWmWillCreateDisplay(const display::Display& display) {
   // A call to this function means a new display is being added, so the
   // DisplayList needs to be updated. Calling AddDisplay() results in