Make drag and drop work on webpage. Also slightly modify drag drop workflow.

chrome/browser/ui/views/tab_contents/native_tab_contents_view_aura.h

Index: chrome/browser/ui/views/tab_contents/native_tab_contents_view_aura.h
diff --git a/chrome/browser/ui/views/tab_contents/native_tab_contents_view_aura.h b/chrome/browser/ui/views/tab_contents/native_tab_contents_view_aura.h
index 7b118c0c2eabc2a5422885352c42222c17ea494b..ccb0568b1fea5719a6a84f1598e72245b80bcce7 100644
--- a/chrome/browser/ui/views/tab_contents/native_tab_contents_view_aura.h
+++ b/chrome/browser/ui/views/tab_contents/native_tab_contents_view_aura.h
@@ -7,8 +7,17 @@
 #pragma once
 
 #include "chrome/browser/ui/views/tab_contents/native_tab_contents_view.h"
+#include "ui/base/events.h"
 #include "ui/views/widget/native_widget_aura.h"
 
+namespace aura {
+class DropTargetEvent;
+}
+
+namespace ui {
+class OSExchangeDataProviderAura;
+}
+
 class TabContents;
 
 class NativeTabContentsViewAura : public views::NativeWidgetAura,
@@ -20,8 +29,6 @@ class NativeTabContentsViewAura : public views::NativeWidgetAura,
 
   TabContents* GetTabContents() const;
 
-  void EndDragging();
-
  private:
   // Overridden from NativeTabContentsView:
   virtual void InitNativeTabContentsView() OVERRIDE;
@@ -43,9 +50,19 @@ class NativeTabContentsViewAura : public views::NativeWidgetAura,
   virtual void OnBoundsChanged(const gfx::Rect& old_bounds,
                                const gfx::Rect& new_bounds) OVERRIDE;
   virtual bool OnMouseEvent(aura::MouseEvent* event) OVERRIDE;
+  virtual void OnDragEntered(const aura::DropTargetEvent& event) OVERRIDE;
+  virtual int OnDragUpdated(const aura::DropTargetEvent& event) OVERRIDE;
+  virtual void OnDragExited() OVERRIDE;
+  virtual int OnPerformDrop(const aura::DropTargetEvent& event) OVERRIDE;
+
+  // Informs the renderer that the drag operation it initiated has ended and
+  // |ops| drag operations were applied.
+  void EndDrag(WebKit::WebDragOperationsMask ops);
 
   internal::NativeTabContentsViewDelegate* delegate_;
 
+  WebKit::WebDragOperationsMask current_drag_op_;
+
   DISALLOW_COPY_AND_ASSIGN(NativeTabContentsViewAura);
 };