Support window.opener after a process swap.

content/browser/tab_contents/tab_contents.cc

Index: content/browser/tab_contents/tab_contents.cc
diff --git a/content/browser/tab_contents/tab_contents.cc b/content/browser/tab_contents/tab_contents.cc
index 26aa66a93671f607c4a759b0b4d211a622564f76..43304027449d9ee4fba93f9fd329bb1bb8e57c53 100644
--- a/content/browser/tab_contents/tab_contents.cc
+++ b/content/browser/tab_contents/tab_contents.cc
@@ -125,14 +125,17 @@
 // - After RDH receives a response and determines that it is safe and not a
 //   download, it pauses the response to first run the old page's onunload
 //   handler.  It does this by asynchronously calling the OnCrossSiteResponse
-//   method of TabContents on the UI thread, which sends a ClosePage message
+//   method of TabContents on the UI thread, which sends a SwapOut message
 //   to the current RVH.
-// - Once the onunload handler is finished, a ClosePage_ACK message is sent to
+// - Once the onunload handler is finished, a SwapOut_ACK message is sent to
 //   the ResourceDispatcherHost, who unpauses the response.  Data is then sent
 //   to the pending RVH.
 // - The pending renderer sends a FrameNavigate message that invokes the
 //   DidNavigate method.  This replaces the current RVH with the
 //   pending RVH and goes back to the NORMAL RendererState.
+// - The previous renderer is kept swapped out in RenderViewHostManager in case
+//   the user goes back.  The process only stays live if another tab is using
+//   it, but if so, the existing frame relationships will be maintained.
 
 namespace {
 
@@ -2018,7 +2021,9 @@ void TabContents::DidNavigate(RenderViewHost* rvh,
 void TabContents::UpdateState(RenderViewHost* rvh,
                               int32 page_id,
                               const std::string& state) {
-  DCHECK(rvh == render_view_host());
+  // Ensure that this state update comes from either the active RVH or one of
+  // the swapped out RVHs.  We don't expect to hear from any other RVHs.
+  DCHECK(rvh == render_view_host() || render_manager_.IsSwappedOut(rvh));
 
   // We must be prepared to handle state updates for any page, these occur
   // when the user is scrolling and entering form data, as well as when we're
@@ -2027,7 +2032,7 @@ void TabContents::UpdateState(RenderViewHost* rvh,
   // NavigationEntry and update it when it is notified via the delegate.
 
   int entry_index = controller_.GetEntryIndexWithPageID(
-      GetSiteInstance(), page_id);
+      rvh->site_instance(), page_id);
   if (entry_index < 0)
     return;
   NavigationEntry* entry = controller_.GetEntryAtIndex(entry_index);