Fix next_page_id_ in a NTP forced to share an existing WebUI process.

content/browser/renderer_host/render_process_host.h

Index: content/browser/renderer_host/render_process_host.h
diff --git a/content/browser/renderer_host/render_process_host.h b/content/browser/renderer_host/render_process_host.h
index 38ff0388e8f795410a07a6fb15c96b95edd430c1..6003203952703b67a9a6b78ad1900c06b2e0b1ee 100644
--- a/content/browser/renderer_host/render_process_host.h
+++ b/content/browser/renderer_host/render_process_host.h
@@ -166,6 +166,9 @@ class CONTENT_EXPORT RenderProcessHost : public IPC::Channel::Sender,
   // Gets the next available routing id.
   virtual int GetNextRoutingID() = 0;
 
+  // Update the max page ID and send the update to the renderer process as well.
+  virtual void UpdateAndSendMaxPageID(int32 page_id) = 0;
+
   // Called on the UI thread to cancel any outstanding resource requests for
   // the specified render widget.
   virtual void CancelResourceRequests(int render_widget_id) = 0;