Fix interstitials on OOPIF-based guests.

content/browser/frame_host/interstitial_page_impl.cc

Index: content/browser/frame_host/interstitial_page_impl.cc
diff --git a/content/browser/frame_host/interstitial_page_impl.cc b/content/browser/frame_host/interstitial_page_impl.cc
index f3357c81587435073d7772e96fa6be9c795743e5..d0c4ffaaebd5c7b0af066134674423878e87b89b 100644
--- a/content/browser/frame_host/interstitial_page_impl.cc
+++ b/content/browser/frame_host/interstitial_page_impl.cc
@@ -754,6 +754,11 @@ void InterstitialPageImpl::CreateNewWindow(
 void InterstitialPageImpl::SetFocusedFrame(FrameTreeNode* node,
                                            SiteInstance* source) {
   frame_tree_.SetFocusedFrame(node, source);
+
+  if (web_contents_) {
+    static_cast<WebContentsImpl*>(web_contents_)
+        ->SetAsFocusedWebContentsIfNecessary();
+  }
 }
 
 void InterstitialPageImpl::CreateNewWidget(int32_t render_process_id,
@@ -977,4 +982,13 @@ void InterstitialPageImpl::UpdateDeviceScaleFactor(double device_scale_factor) {
   web_contents_impl->UpdateDeviceScaleFactor(device_scale_factor);
 }
 
+RenderWidgetHostInputEventRouter* InterstitialPageImpl::GetInputEventRouter() {
+  WebContentsImpl* web_contents_impl =
+      static_cast<WebContentsImpl*>(web_contents_);
+  if (!web_contents_impl)
+    return nullptr;
+
+  return web_contents_impl->GetInputEventRouter();
+}
+
 }  // namespace content