Plumb event flags (shift/alt/ctrl modifiers) for drag/drop events to WebKit.

ash/drag_drop/drag_drop_controller.cc

 // Copyright (c) 2012 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.
 
 #include "ash/drag_drop/drag_drop_controller.h"
 
 #include "ash/drag_drop/drag_image_view.h"
 #include "ash/shell.h"
 #include "base/message_loop.h"
 #include "ui/aura/client/drag_drop_delegate.h"
@@ skipping 86 matching lines @@
         delegate->OnDragExited();
       drag_window_->RemoveObserver(this);
     }
     drag_window_ = target;
     drag_window_->AddObserver(this);
     if ((delegate = aura::client::GetDragDropDelegate(drag_window_))) {
       aura::DropTargetEvent e(*drag_data_,
                               event.location(),
                               event.root_location(),
                               drag_operation_);
+      e.set_flags(event.flags());
       delegate->OnDragEntered(e);
     }
   } else {
     if ((delegate = aura::client::GetDragDropDelegate(drag_window_))) {
       aura::DropTargetEvent e(*drag_data_,
                               event.location(),
                               event.root_location(),
                               drag_operation_);
+      e.set_flags(event.flags());
       int op = delegate->OnDragUpdated(e);
       gfx::NativeCursor cursor = (op == ui::DragDropTypes::DRAG_NONE)?
           ui::kCursorNoDrop : ui::kCursorCopy;
       Shell::GetRootWindow()->SetCursor(cursor);
     }
   }
 
   DCHECK(drag_image_.get());
   if (drag_image_->visible()) {
     drag_image_->SetScreenPosition(
         event.root_location().Subtract(drag_image_offset_));
   }
 }
 
 void DragDropController::Drop(aura::Window* target,
                               const aura::LocatedEvent& event) {
   Shell::GetRootWindow()->SetCursor(ui::kCursorPointer);
   aura::client::DragDropDelegate* delegate = NULL;
 
   // We must guarantee that a target gets a OnDragEntered before Drop. WebKit
   // depends on not getting a Drop without DragEnter. This behavior is
   // consistent with drag/drop on other platforms.
   if (target != drag_window_)
     DragUpdate(target, event);
   DCHECK(target == drag_window_);
 
   if ((delegate = aura::client::GetDragDropDelegate(target))) {
     aura::DropTargetEvent e(
         *drag_data_, event.location(), event.root_location(), drag_operation_);
+    e.set_flags(event.flags());
     drag_operation_ = delegate->OnPerformDrop(e);
     if (drag_operation_ == 0)
       StartCanceledAnimation();
     else
       drag_image_.reset();
   } else {
     drag_image_.reset();
   }
 
   Cleanup();
@@ skipping 113 matching lines @@
 void DragDropController::Cleanup() {
   if (drag_window_)
     drag_window_->RemoveObserver(this);
   drag_window_ = NULL;
   drag_data_ = NULL;
   drag_drop_in_progress_ = false;
 }
 
 }  // namespace internal
 }  // namespace ash