Generate thumbnails in the browser process.

chrome/browser/renderer_host/render_view_host.cc

Index: chrome/browser/renderer_host/render_view_host.cc
diff --git a/chrome/browser/renderer_host/render_view_host.cc b/chrome/browser/renderer_host/render_view_host.cc
index c4f3ba64251788f4ec622d706287364c639e0d76..fa3daf541eabfa5b10d347cb07630796933e0225 100644
--- a/chrome/browser/renderer_host/render_view_host.cc
+++ b/chrome/browser/renderer_host/render_view_host.cc
@@ -857,6 +857,7 @@ bool RenderViewHost::OnMessageReceived(const IPC::Message& msg) {
 #endif
     IPC_MESSAGE_HANDLER(ViewHostMsg_PagesReadyForPreview,
                         OnPagesReadyForPreview)
+    IPC_MESSAGE_HANDLER(ViewHostMsg_UpdateScrollOffset, OnUpdateScrollOffset)
     // Have the super handle all other messages.
     IPC_MESSAGE_UNHANDLED(handled = RenderWidgetHost::OnMessageReceived(msg))
   IPC_END_MESSAGE_MAP_EX()
@@ -2017,3 +2018,7 @@ void RenderViewHost::OnPagesReadyForPreview(
   // Send the printingDone msg for now.
   Send(new ViewMsg_PrintingDone(routing_id(), params.document_cookie, true));
 }
+
+void RenderViewHost::OnUpdateScrollOffset(const gfx::Size& scroll_offset) {
+  last_scroll_offset_ = scroll_offset;
+}