[MacViews] Fix Drag and Drop bugs

Made changes so that MacViews can accept drops from
other applications.

BUG=599585

Review-Url: https://codereview.chromium.org/2307633002
Cr-Commit-Position: refs/heads/master@{#416419}

ui/base/dragdrop/drag_drop_types.h

@@ -35,6 +35,7 @@ class UI_BASE_EXPORT DragDropTypes {
 
 #if defined(OS_MACOSX)
   static uint64_t DragOperationToNSDragOperation(int drag_operation);
+  static int NSDragOperationToDragOperation(uint64_t ns_drag_operation);
 #endif
 };
 

ui/base/dragdrop/drag_drop_types_mac.mm

@@ -21,4 +21,18 @@ uint64_t ui::DragDropTypes::DragOperationToNSDragOperation(int drag_operation) {
   return ns_drag_operation;
 }
 
+int ui::DragDropTypes::NSDragOperationToDragOperation(
+    uint64_t ns_drag_operation) {
+  NSUInteger drag_operation = DRAG_NONE;
+
+  if (ns_drag_operation & NSDragOperationLink)
+    drag_operation |= DRAG_LINK;
+  if (ns_drag_operation & NSDragOperationCopy)
+    drag_operation |= DRAG_COPY;
+  if (ns_drag_operation & NSDragOperationMove)
+    drag_operation |= DRAG_MOVE;
+
+  return drag_operation;
+}
+
 }  // namespace ui

ui/views/cocoa/drag_drop_client_mac.mm

@@ -132,6 +132,8 @@ NSDragOperation DragDropClientMac::DragUpdate(id<NSDraggingInfo> sender) {
   if (!data_source_.get()) {
     data_source_.reset([[CocoaDragDropDataProvider alloc]
         initWithPasteboard:[sender draggingPasteboard]]);
+    operation_ = ui::DragDropTypes::NSDragOperationToDragOperation(
+        [sender draggingSourceOperationMask]);
   }
 
   drag_operation = drop_helper_.OnDragOver(
@@ -144,6 +146,8 @@ NSDragOperation DragDropClientMac::Drop(id<NSDraggingInfo> sender) {
   int drag_operation = drop_helper_.OnDrop(
       *[data_source_ data], LocationInView([sender draggingLocation]),
       operation_);
+  data_source_.reset();
+  operation_ = 0;
   return ui::DragDropTypes::DragOperationToNSDragOperation(drag_operation);
 }
 

ui/views/cocoa/drag_drop_client_mac_unittest.mm

@@ -61,7 +61,7 @@ using base::ASCIIToUTF16;
 }
 
 - (NSDragOperation)draggingSourceOperationMask {
-  return NSDragOperationNone;
+  return NSDragOperationEvery;
 }
 
 - (NSWindow*)draggingDestinationWindow {