Should not call FocusController::setFocusedFrame() for detached frame

third_party/WebKit/Source/core/page/FocusController.cpp

Index: third_party/WebKit/Source/core/page/FocusController.cpp
diff --git a/third_party/WebKit/Source/core/page/FocusController.cpp b/third_party/WebKit/Source/core/page/FocusController.cpp
index c7d11a226f30bdcff86214c2462d43f70a5ee4cc..a5bd053d02a018cff93abb58b57cbbbbfe792803 100644
--- a/third_party/WebKit/Source/core/page/FocusController.cpp
+++ b/third_party/WebKit/Source/core/page/FocusController.cpp
@@ -772,6 +772,11 @@ void FocusController::focusDocumentView(Frame* frame, bool notifyEmbedder)
             dispatchFocusEvent(*document, *focusedElement);
     }
 
+    // dispatchBlurEvent/dispatchFocusEvent could have changed the focused frame, or
+    // detached the frame.
+    if (newFocusedFrame && !newFocusedFrame->selection().isAvailable())

[yosin_UTC9, 2016/07/21 06:10:10]

It is better to use |newFocusedFrame && newFocusedFrame->view()|,
selection is availability isn't directly related to frame availability.

[kochi, 2016/07/21 06:55:26]

Done.

+        return;
+
     setFocusedFrame(frame, notifyEmbedder);
 }
 
@@ -1115,9 +1120,10 @@ void FocusController::setActive(bool active)
         // Invalidate all custom scrollbars because they support the CSS
         // window-active attribute. This should be applied to the entire page so
         // we invalidate from the root FrameView instead of just the focused.
-        if (FrameView* view = toLocalFrame(frame)->localFrameRoot()->document()->view())
+        if (FrameView* view = toLocalFrame(frame)->localFrameRoot()->document()->view()) {
             view->invalidateAllCustomScrollbarsOnActiveChanged();
-        toLocalFrame(frame)->selection().pageActivationChanged();
+            toLocalFrame(frame)->selection().pageActivationChanged();

[yosin_UTC9, 2016/07/21 06:10:10]

Can we assume that |localFrameRoot()->view() != nullptr| implies
|frame->selection().isAvailable()|?
It seems this assumption is weak, e.g. |frame| is inside remote frame.
It is better to check frame->selection().isAvailable() instead of
|localFrameRoot()->view() != nullptr|.

[kochi, 2016/07/21 06:55:26]

Agree that |->view()| doesn't imply |selection().isAvailable()| is true.
Check added.

Done.

+        }
     }
 }