Why this CL triggers an OilPan crash.

content/browser/renderer_host/render_view_host_impl.cc

Index: content/browser/renderer_host/render_view_host_impl.cc
diff --git a/content/browser/renderer_host/render_view_host_impl.cc b/content/browser/renderer_host/render_view_host_impl.cc
index 51c20a6a5edc7613df5df254e71128c4a70f7af2..483e83785d96eb8d3214b68796ed779a12e3853c 100644
--- a/content/browser/renderer_host/render_view_host_impl.cc
+++ b/content/browser/renderer_host/render_view_host_impl.cc
@@ -34,6 +34,7 @@
 #include "content/browser/child_process_security_policy_impl.h"
 #include "content/browser/dom_storage/session_storage_namespace_impl.h"
 #include "content/browser/frame_host/frame_tree.h"
+#include "content/browser/frame_host/render_frame_proxy_host.h"
 #include "content/browser/gpu/compositor_util.h"
 #include "content/browser/gpu/gpu_data_manager_impl.h"
 #include "content/browser/gpu/gpu_process_host.h"
@@ -304,7 +305,26 @@ bool RenderViewHostImpl::CreateRenderView(
   }
   params->session_storage_namespace_id =
       delegate_->GetSessionStorageNamespace(instance_.get())->id();
-  // Ensure the RenderView sets its opener correctly.
+  if (main_frame_routing_id_ != MSG_ROUTING_NONE) {
+    params->browsing_instance_id = RenderFrameHostImpl::FromID(
+        GetProcess()->GetID(), main_frame_routing_id_)
+          ->GetSiteInstance()
+          ->GetBrowsingInstanceId();
+  } else if (opener_frame_route_id != MSG_ROUTING_NONE) {
+    params->browsing_instance_id = RenderFrameHostImpl::FromID(
+        GetProcess()->GetID(), opener_frame_route_id)
+          ->GetSiteInstance()
+          ->GetBrowsingInstanceId();
+  } else if (proxy_route_id != MSG_ROUTING_NONE) {
+    SiteInstance* site_instance = RenderFrameProxyHost::FromID(
+        GetProcess()->GetID(), proxy_route_id)
+          ->GetSiteInstance();
+    params->browsing_instance_id = static_cast<SiteInstanceImpl*>(site_instance)
+          ->GetBrowsingInstanceId();
+  } else {
+    CHECK(false);
+    params->browsing_instance_id = -1;
+  }
   params->opener_frame_route_id = opener_frame_route_id;
   params->swapped_out = !is_active_;
   params->replicated_frame_state = replicated_frame_state;