MacViews: Implemented Drag & Drop

ui/views/cocoa/bridged_native_widget.mm

 // 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.
 
 #import "ui/views/cocoa/bridged_native_widget.h"
 
 #import <objc/runtime.h>
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/logging.h"
 #import "base/mac/foundation_util.h"
 #include "base/mac/mac_util.h"
 #import "base/mac/sdk_forward_declarations.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "ui/accelerated_widget_mac/window_resize_helper_mac.h"
 #import "ui/base/cocoa/constrained_window/constrained_window_animation.h"
 #include "ui/base/hit_test.h"
 #include "ui/base/ime/input_method.h"
 #include "ui/base/ime/input_method_factory.h"
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
 #include "ui/gfx/geometry/dip_util.h"
 #import "ui/gfx/mac/coordinate_conversion.h"
 #import "ui/gfx/mac/nswindow_frame_controls.h"
 #import "ui/views/cocoa/bridged_content_view.h"
+#import "ui/views/cocoa/drag_drop_client_mac.h"
 #import "ui/views/cocoa/cocoa_mouse_capture.h"
 #include "ui/views/cocoa/tooltip_manager_mac.h"
 #import "ui/views/cocoa/views_nswindow_delegate.h"
 #import "ui/views/cocoa/widget_owner_nswindow_adapter.h"
 #include "ui/views/view.h"
 #include "ui/views/views_delegate.h"
 #include "ui/views/widget/native_widget_mac.h"
 #include "ui/views/widget/widget.h"
 #include "ui/views/widget/widget_aura_utils.h"
 #include "ui/views/widget/widget_delegate.h"
@@ skipping 474 matching lines @@
             animate:NO];
 }
 
 void BridgedNativeWidget::SetRootView(views::View* view) {
   if (view == [bridged_view_ hostedView])
     return;
 
   // If this is ever false, the compositor will need to be properly torn down
   // and replaced, pointing at the new view.
   DCHECK(!view || !compositor_widget_);
 

[tapted, 2016/06/01 01:57:01]

hm - I think we do still need the drag_drop_client_.reset() here, so that
accesses from the NSView* get nerfed. We probably just have to change a DCHECK
in ViewRemoved into an `if`

[spqchan, 2016/06/01 19:09:28]

Done.

   [bridged_view_ clearView];
   bridged_view_.reset();
   // Note that there can still be references to the old |bridged_view_|
   // floating around in Cocoa libraries at this point. However, references to
   // the old views::View will be gone, so any method calls will become no-ops.
 
   if (view) {
     bridged_view_.reset([[BridgedContentView alloc] initWithView:view]);
+    drag_drop_client_.reset(new DragDropClientMac(this, view));
+
     // Objective C initializers can return nil. However, if |view| is non-NULL
     // this should be treated as an error and caught early.
     CHECK(bridged_view_);
   }
   [window_ setContentView:bridged_view_];
 }
 
 void BridgedNativeWidget::SetVisibilityState(WindowVisibilityState new_state) {
   // Ensure that:
   //  - A window with an invisible parent is not made visible.
@@ skipping 763 matching lines @@
   [bridged_view_ setMouseDownCanMoveWindow:draggable];
   // AppKit will not update its cache of mouseDownCanMoveWindow unless something
   // changes. Previously we tried adding an NSView and removing it, but for some
   // reason it required reposting the mouse-down event, and didn't always work.
   // Calling the below seems to be an effective solution.
   [window_ setMovableByWindowBackground:NO];
   [window_ setMovableByWindowBackground:YES];
 }
 
 }  // namespace views