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

content/public/browser/render_view_host.h

Index: content/public/browser/render_view_host.h
diff --git a/content/public/browser/render_view_host.h b/content/public/browser/render_view_host.h
index 991c868c9a23d38b9ae016f7637ddd55f1c74cbc..3d57db1d92fa7268930bbfa4f070c2e73728379d 100644
--- a/content/public/browser/render_view_host.h
+++ b/content/public/browser/render_view_host.h
@@ -119,14 +119,17 @@ class CONTENT_EXPORT RenderViewHost : virtual public RenderWidgetHost {
       const WebDropData& drop_data,
       const gfx::Point& client_pt,
       const gfx::Point& screen_pt,
-      WebKit::WebDragOperationsMask operations_allowed) = 0;
+      WebKit::WebDragOperationsMask operations_allowed,
+      int key_modifiers) = 0;
   virtual void DragTargetDragOver(
       const gfx::Point& client_pt,
       const gfx::Point& screen_pt,
-      WebKit::WebDragOperationsMask operations_allowed) = 0;
+      WebKit::WebDragOperationsMask operations_allowed,
+      int key_modifiers) = 0;
   virtual void DragTargetDragLeave() = 0;
   virtual void DragTargetDrop(const gfx::Point& client_pt,
-                              const gfx::Point& screen_pt) = 0;
+                              const gfx::Point& screen_pt,
+                              int key_modifiers) = 0;
 
   // Instructs the RenderView to automatically resize and send back updates
   // for the new size.