MacViews: Implemented Drag & Drop

ui/views/cocoa/bridged_content_view.h

Index: ui/views/cocoa/bridged_content_view.h
diff --git a/ui/views/cocoa/bridged_content_view.h b/ui/views/cocoa/bridged_content_view.h
index 20111a8bf6b229fe91a147d51dea73e71118fa60..04ad1ce5c45590a56c17bf9d829d5c5796387293 100644
--- a/ui/views/cocoa/bridged_content_view.h
+++ b/ui/views/cocoa/bridged_content_view.h
@@ -10,12 +10,14 @@
 #include "base/strings/string16.h"
 #import "ui/base/cocoa/tool_tip_base_view.h"
 #import "ui/base/cocoa/tracking_area.h"
+#include "ui/views/cocoa/cocoa_drag_drop_manager.h"
 
 namespace ui {
 class TextInputClient;
 }
 
 namespace views {
+class CocoaDragDropManager;
 class View;
 }
 
@@ -28,6 +30,9 @@ class View;
   // Weak. The hosted RootView, owned by hostedView_->GetWidget().
   views::View* hostedView_;
 
+  // Weak. Owned by BridgedNativeWidget.
+  views::CocoaDragDropManager* drag_drop_manager_;

[tapted, 2016/05/11 12:36:15]

It might be nicer to have a helper function that does

BridgedNativeWidget* bridge =
    NativeWidgetMac::GetBridgeForNativeWindow([self window]);
return bridge ? bridge->drag_drop_manager() : nullptr;

ObjC objects holding on to C++ objects tends to lead to tricky lifetime problems
due to reference counting.

[spqchan, 2016/05/23 21:26:21]

Done.

+
   // Weak. If non-null the TextInputClient of the currently focused View in the
   // hierarchy rooted at |hostedView_|. Owned by the focused View.
   ui::TextInputClient* textInputClient_;
@@ -62,7 +67,8 @@ class View;
 @property(assign) BOOL mouseDownCanMoveWindow;
 
 // Initialize the NSView -> views::View bridge. |viewToHost| must be non-NULL.
-- (id)initWithView:(views::View*)viewToHost;
+- (id)initWithView:(views::View*)viewToHost
+    dragDropManager:(views::CocoaDragDropManager*)dragDropManager;
 
 // Clear the hosted view. For example, if it is about to be destroyed.
 - (void)clearView;