Algorithm for deciding if a frame's selection should be hidden

third_party/WebKit/Source/core/editing/FrameSelection.cpp

Index: third_party/WebKit/Source/core/editing/FrameSelection.cpp
diff --git a/third_party/WebKit/Source/core/editing/FrameSelection.cpp b/third_party/WebKit/Source/core/editing/FrameSelection.cpp
index f639ca8f81ff559310430e556eec87b95de382ab..544b556c81cdcbd551b75c7346d14b0969e70e49 100644
--- a/third_party/WebKit/Source/core/editing/FrameSelection.cpp
+++ b/third_party/WebKit/Source/core/editing/FrameSelection.cpp
@@ -250,7 +250,7 @@ void FrameSelection::DidSetSelectionDeprecated(SetSelectionOptions options,
   }
 
   frame_caret_->StopCaretBlinkTimer();
-  UpdateAppearance(LayoutSelection::PaintHint::kPaint);
+  UpdateAppearance();
 
   // Always clear the x position used for vertical arrow navigation.
   // It will be restored by the vertical arrow navigation code if necessary.
@@ -335,26 +335,7 @@ void FrameSelection::DidChangeFocus() {
   // Hits in
   // virtual/gpu/compositedscrolling/scrollbars/scrollbar-miss-mousemove-disabled.html
   DisableCompositingQueryAsserts disabler;
-
-  // No focused element means document root has focus.
-  const Element* const focus = GetDocument().FocusedElement()
-                                   ? GetDocument().FocusedElement()
-                                   : GetDocument().documentElement();
-
-  // Protection against LayoutTests/editing/selection/selection-crash.html
-  if (!focus) {
-    frame_caret_->ScheduleVisualUpdateForPaintInvalidationIfNeeded();
-    text_control_focused_ = false;
-    return;
-  }
-
-  // Hide the selection when focus goes away from a text-field and into
-  // something that is not a text-field. When focus enters another text-field we
-  // do not need to update appearance; the appearance is updated when the new
-  // selection is set.
-  if (text_control_focused_ && !focus->IsTextControl())
-    UpdateAppearance(LayoutSelection::PaintHint::kHide);
-  text_control_focused_ = focus->IsTextControl();
+  UpdateAppearance();
 }
 
 static DispatchEventResult DispatchSelectStart(
@@ -444,6 +425,48 @@ void FrameSelection::Clear() {
   SetSelection(SelectionInDOMTree());
 }
 
+bool FrameSelection::IsHidden() {

[yosin_UTC9, 2017/04/28 07:57:09]

I would like to call this function as |HasFocus()| or |IsActive()|.
Because of even if we don't paint selection, selection is still available.

+  // No focused element means document root has focus.
+  const Element* const focus_element = GetDocument().FocusedElement()
+                                           ? GetDocument().FocusedElement()
+                                           : GetDocument().documentElement();
+  if (!focus_element)
+    return true;
+
+  const Node* start = ComputeVisibleSelectionInDOMTreeDeprecated()
+                          .Start()
+                          .ComputeContainerNode();
+  if (!start)
+    return true;
+
+  if (focus_element->IsTextControl())
+    return !focus_element->ContainsIncludingHostElements(*start);
+
+  bool has_editable_style = HasEditableStyle(*start);
+  const Node* current = start;
+  do {
+    if (current == focus_element)
+      return false;
+    if (has_editable_style && !HasEditableStyle(*current)) {
+      // We exited an editable subtree without finding focus.
+      TextControlElement* in_text_control =
+          EnclosingTextControl(GetSelectionInDOMTree().Base());
+      if (in_text_control || !GetSelectionInDOMTree().IsRange()) {
+        // Example to trigger this:
+        //  <div style="background: orange; padding: 20%;
+        //    user-select: none" tabindex="-1">
+        //  <input value="click orange" autofocus></div>
+        // When clicking (focusing) the orange <div>, <input>'s selection
+        // looses focus (it should not receive input).
+        return true;
+      }
+    }
+    current = current->ParentOrShadowHostNode();
+  } while (current);
+
+  return false;

[yosin_UTC9, 2017/04/28 01:14:33]

We also need to handle Range selection case.
We should paint range selection if focused element in range, e.g.
selection.start <= focused_element < selection.end.

[hugoh_UTC2, 2017/04/28 06:55:12]

The test I made for that case, see TEST_F(FrameSelectionTest,
RangeContainsFocus), passes. Is that test OK?

[yosin_UTC9, 2017/04/28 07:57:09]

Yes, it is what I expected.

+}
+
 void FrameSelection::DocumentAttached(Document* document) {
   DCHECK(document);
   use_secure_keyboard_entry_when_active_ = false;
@@ -792,15 +815,13 @@ void FrameSelection::CommitAppearanceIfNeeded() {
 }
 
 void FrameSelection::DidLayout() {
-  // Upon relayout, a hidden selection must be kept hidden and a visible
-  // selection must be kept visible.
-  UpdateAppearance(LayoutSelection::PaintHint::kKeep);
+  UpdateAppearance();
 }
 
-void FrameSelection::UpdateAppearance(LayoutSelection::PaintHint hint) {
+void FrameSelection::UpdateAppearance() {
   DCHECK(!frame_->ContentLayoutItem().IsNull());
   frame_caret_->ScheduleVisualUpdateForPaintInvalidationIfNeeded();
-  layout_selection_->SetHasPendingSelection(hint);
+  layout_selection_->SetHasPendingSelection();
 }
 
 void FrameSelection::NotifyLayoutObjectOfSelectionChange(
@@ -989,7 +1010,7 @@ void FrameSelection::RevealSelection(const ScrollAlignment& alignment,
       document_loader->GetInitialScrollState().was_scrolled_by_user = true;
     if (start.AnchorNode()->GetLayoutObject()->ScrollRectToVisible(
             rect, alignment, alignment))
-      UpdateAppearance(LayoutSelection::PaintHint::kPaint);
+      UpdateAppearance();
   }
 }