mus: Implement interwindow drag and drop

services/ui/public/interfaces/window_tree.mojom

 // 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.
 
 module ui.mojom;
 
 import "cc/ipc/surface_id.mojom";
 import "services/ui/public/interfaces/cursor.mojom";
 import "services/ui/public/interfaces/event_matcher.mojom";
 import "services/ui/public/interfaces/mus_constants.mojom";
 import "services/ui/public/interfaces/surface.mojom";
 import "services/ui/public/interfaces/window_manager.mojom";
 import "services/ui/public/interfaces/window_manager_constants.mojom";
 import "services/ui/public/interfaces/window_tree_constants.mojom";
+import "skia/public/interfaces/bitmap.mojom";
 import "ui/events/mojo/event.mojom";
 import "ui/gfx/geometry/mojo/geometry.mojom";
 import "ui/platform_window/mojo/text_input_state.mojom";
 
 // Windows are identified by a uint32. The upper 16 bits are the connection id,
 // and the lower 16 the id assigned by the client.
 //
 // The root window is identified with a connection id of 0, and value of 1.
 //
 // Most functions to the WindowTree take a change_id parameter. When
@@ skipping 81 matching lines @@
   // TODO(sky): convert additional_client_areas to a path.
   SetClientArea(uint32 window_id,
                 gfx.mojom.Insets insets,
                 array<gfx.mojom.Rect>? additional_client_areas);
 
   // Mouse events outside a hit test mask do not hit the window. The |mask| is
   // in window local coordinates. Pass null to clear the mask.
   // TODO(jamescook): Convert |mask| to a path. http://crbug.com/613210
   SetHitTestMask(uint32 window_id, gfx.mojom.Rect? mask);
 
+  // Called by clients that want to accept drags. Windows default
+  // to this being disabled; a window must actively opt-in to
+  // receiving Drag*() calls.
+  SetCanAcceptDrags(uint32 window_id, bool accepts_drags);
+
   // Sets the visibility of the specified window to |visible|. Connections are
   // allowed to change the visibility of any window they have created, as well
   // as any of their roots.
   SetWindowVisibility(uint32 change_id, uint32 window_id, bool visible);
 
   // Sets an individual named property. Setting an individual property to null
   // deletes the property.
   SetWindowProperty(uint32 change_id,
                     uint32 window_id,
                     string name,
@@ skipping 137 matching lines @@
   // Tells the window manager to start moving the window. OnChangeCompleted is
   // called on whether the move was canceled. Because there's a delay between
   // when a client sends this message and when the window manager starts acting
   // on it, pass the cursor location at the start of the move.
   PerformWindowMove(uint32 change_id, uint32 window_id, MoveLoopSource source,
                     gfx.mojom.Point cursor);
 
   // Tells the window manager to cancel any in progress window move started with
   // StartWindowMove() and to revert the window bounds to how they were.
   CancelWindowMove(uint32 window_id);
+
+  // Called by the client to start a drag operation.
+  //
+  // This will cause the window server to create a window with
+  // |drag_representation| and start processing events for drag and
+  // drop. It will set the clipboard’s DRAG clipboard to |drag_data|
+  // (this is part of this interface since mojom.Clipboard is usually
+  // on a different pipe).
+  PerformDragDrop(uint32 change_id,
+                  uint32 source_window_id,
+                  map<string, array<uint8>> drag_data,
+                  uint32 drag_operation,
+                  gfx.mojom.Point cursor_location,
+                  skia.mojom.Bitmap drag_representation);
 };
 
 // Changes to windows are not sent to the connection that originated the
 // change. For example, if connection 1 changes the bounds of a window by
 // calling SetWindowBounds(), connection 1 does not receive
 // OnWindowBoundsChanged().
 interface WindowTreeClient {
   // Invoked when the client application has been embedded at |root|.
   // See Embed() on WindowTree for more details. |tree| will be a handle back to
   // the window manager service, unless the connection is to the root connection
@@ skipping 110 matching lines @@
 
   // Called in two distinct cases: when a window known to the connection gains
   // focus, or when focus moves from a window known to the connection to a
   // window not known to the connection. In the later case |focused_window_id|
   // is 0. As with other functions this is only called if the client did not
   // initiate the change.
   OnWindowFocused(uint32 focused_window_id);
 
   OnWindowPredefinedCursorChanged(uint32 window_id, Cursor cursor_id);
 
+  // Called when the mouse cursor enters a window that has opted into
+  // accepting drags through SetAcceptsDrags(), providing a list
+  // of available mime types.  Returns a bitmask of the supported
+  // operations.
+  OnDragEnter(uint32 window,
+              map<string, array<uint8>> drag_data,
+              uint32 key_state,
+              gfx.mojom.Point position,
+              uint32 effect_bitmask) => (uint32 supported_op_bitmask);
+
+  // Called when the pointer moves over the window after the initial
+  // DragEnter. Returns a bitmask of the supported operations at this
+  // location.
+  OnDragOver(uint32 window,
+             uint32 key_state,
+             gfx.mojom.Point position,
+             uint32 effect_bitmask) => (uint32 supported_op_bitmask);
+
+  // Called when the pointer leaves a window or if the drop is
+  // canceled.
+  OnDragLeave(uint32 window);
+
+  // Called when the drop occurs on a window. Returns the action
+  // taken.
+  OnDragDrop(uint32 window,
+             uint32 key_state,
+             gfx.mojom.Point position,
+             uint32 effect_bitmask) => (uint32 effect_taken);
+
   // A change initiated from the client has completed. See description of
   // change ids for details.
   OnChangeCompleted(uint32 change_id, bool success);
 
   // The WindowManager is requesting the specified window to close. If the
   // client allows the change it should delete the window.
   RequestClose(uint32 window_id);
 
   // See description of WindowManager for details.
   GetWindowManager(associated WindowManager& internal);
 };
 
 // Mus provides this interface as a way for clients to connect and obtain a
 // WindowTree handle with a supplied WindowTreeClient handle. The
 // WindowTreeClient has no roots, use NewTopLevelWindow() to create one.
 interface WindowTreeFactory {
   CreateWindowTree(WindowTree& tree_request, WindowTreeClient client);
 };