Disable page ID vs PageState CHECK in release builds for now.

content/renderer/render_frame_impl.cc

Index: content/renderer/render_frame_impl.cc
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index d2030c35e017a83ed17e6526dbb2907d173b90c1..b676e3e19e1dffbdcb8e66c5b2e6eaf0495cccaa 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -5615,7 +5615,11 @@ void RenderFrameImpl::NavigateInternal(
     }
 
     // A session history navigation should have been accompanied by state.
-    CHECK_EQ(request_params.page_id, -1);
+    // TODO(creis): This is known to be failing in UseSubframeNavigationEntries
+    // in https://crbug.com/568703, when the PageState on a FrameNavigationEntry
+    // is unexpectedly empty.  Until the cause is found, keep this as a DCHECK
+    // and load the URL without PageState.
+    DCHECK_EQ(request_params.page_id, -1);
 
     should_load_request = true;
   }