aura: Fix a couple of drag drop issues:

ui/aura/root_window.cc

Index: ui/aura/root_window.cc
diff --git a/ui/aura/root_window.cc b/ui/aura/root_window.cc
index 159a1c6931c8cbdedac8a9d5fdc0099e526c665b..d7fb311be6419908602e5bff51d1fb109d8a2c59 100644
--- a/ui/aura/root_window.cc
+++ b/ui/aura/root_window.cc
@@ -14,6 +14,7 @@
 #include "ui/aura/aura_switches.h"
 #include "ui/aura/client/activation_client.h"
 #include "ui/aura/client/capture_client.h"
+#include "ui/aura/client/drag_drop_client.h"
 #include "ui/aura/client/event_client.h"
 #include "ui/aura/client/screen_position_client.h"
 #include "ui/aura/env.h"
@@ -218,6 +219,11 @@ gfx::Point RootWindow::GetHostOrigin() const {
 }
 
 void RootWindow::SetCursor(gfx::NativeCursor cursor) {
+  // If a drag is in progress, the DragDropClient should override the cursor.
+  client::DragDropClient* dnd_client = client::GetDragDropClient(this);
+  if (dnd_client && dnd_client->IsDragDropInProgress())
+    cursor = dnd_client->GetDragCursor();
+
   last_cursor_ = cursor;
   // A lot of code seems to depend on NULL cursors actually showing an arrow,
   // so just pass everything along to the host.