Let PaintAtAck send an int tag instead of the TransportDIB handle.

chrome/renderer/render_widget.cc

Index: chrome/renderer/render_widget.cc
diff --git a/chrome/renderer/render_widget.cc b/chrome/renderer/render_widget.cc
index 5b5058e7a8167c9caae6aecafd73e7842329c891..a5f3c0b493a6420b287dedeffb238ed0abe4534f 100644
--- a/chrome/renderer/render_widget.cc
+++ b/chrome/renderer/render_widget.cc
@@ -742,6 +742,7 @@ void RenderWidget::OnImeConfirmComposition() {
 // This message causes the renderer to render an image of the
 // desired_size, regardless of whether the tab is hidden or not.
 void RenderWidget::OnMsgPaintAtSize(const TransportDIB::Handle& dib_handle,
+                                    int tag,
                                     const gfx::Size& page_size,
                                     const gfx::Size& desired_size) {
   if (!webwidget_ || dib_handle == TransportDIB::DefaultHandleValue())
@@ -750,9 +751,7 @@ void RenderWidget::OnMsgPaintAtSize(const TransportDIB::Handle& dib_handle,
   if (page_size.IsEmpty() || desired_size.IsEmpty()) {
     // If one of these is empty, then we just return the dib we were
     // given, to avoid leaking it.
-    Send(new ViewHostMsg_PaintAtSize_ACK(routing_id_,
-                                         dib_handle,
-                                         desired_size));
+    Send(new ViewHostMsg_PaintAtSize_ACK(routing_id_, tag, desired_size));
     return;
   }
 
@@ -807,7 +806,7 @@ void RenderWidget::OnMsgPaintAtSize(const TransportDIB::Handle& dib_handle,
   // Return the widget to its previous size.
   webwidget_->resize(old_size);
 
-  Send(new ViewHostMsg_PaintAtSize_ACK(routing_id_, dib_handle, bounds.size()));
+  Send(new ViewHostMsg_PaintAtSize_ACK(routing_id_, tag, bounds.size()));
 }
 
 void RenderWidget::OnMsgRepaint(const gfx::Size& size_to_paint) {