Pass location in screen coordinates to DragDropClient::StartDragAndDrop()

This CL:
- Avoids converting from screen coordinates in
  WebContentsViewAura::StartDragging() and back to screen coordinates in
  DragDropController::StartDragAndDrop()
- Passes the location in the correct coordinates to StartDragAndDrop() in
  DragDownloadItem() in drag_download_item_views.cc

BUG=456619
TEST=Manual, see bug

Review URL: https://codereview.chromium.org/901563005

Cr-Commit-Position: refs/heads/master@{#317888}

1 files changed, 3 insertions, 3 deletions

diff --git a/ui/wm/public/drag_drop_client.h b/ui/wm/public/drag_drop_client.h
index 62a2355..e9989a5 100644
--- a/ui/wm/public/drag_drop_client.h
+++ b/ui/wm/public/drag_drop_client.h
@@ -28,12 +28,12 @@ class AURA_EXPORT DragDropClient {
   virtual ~DragDropClient() {}
 
   // Initiates a drag and drop session. Returns the drag operation that was
-  // applied at the end of the drag drop session. |root_location| is in the
-  // root Window's coordinate system.
+  // applied at the end of the drag drop session. |screen_location| is in
+  // screen coordinates.
   virtual int StartDragAndDrop(const ui::OSExchangeData& data,
                                aura::Window* root_window,
                                aura::Window* source_window,
-                               const gfx::Point& root_location,
+                               const gfx::Point& screen_location,
                                int operation,
                                ui::DragDropTypes::DragEventSource source) = 0;