document.patch

    Document focused element was set to nullptr on detach, but client
    wasn't informed so it still believes that the current focused url
    to be the one that no longer exists. It's a bit of a mystery how
    this code every worked though.
    
    BUG=425584

diff --git a/third_party/WebKit/Source/core/dom/Document.cpp b/third_party/WebKit/Source/core/dom/Document.cpp
index 4427c73..d4a4bac 100644
--- a/third_party/WebKit/Source/core/dom/Document.cpp
+++ b/third_party/WebKit/Source/core/dom/Document.cpp
@@ -2208,6 +2208,10 @@ void Document::detach(const AttachContext& context)
     m_activeHoverElement = nullptr;
     m_autofocusElement = nullptr;
 
+    // Notify client that focused node has changed to empty so that it can clear the current one.
+    if (frameHost())
+        frameHost()->chrome().focusedNodeChanged(nullptr);
+
     m_renderView = 0;
     ContainerNode::detach(context);