Do not send redundant selectionchange-events (decouple focus)

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

Index: third_party/WebKit/Source/core/editing/LayoutSelection.cpp
diff --git a/third_party/WebKit/Source/core/editing/LayoutSelection.cpp b/third_party/WebKit/Source/core/editing/LayoutSelection.cpp
index 540146afea59317b2f41c95f2de8b3f74415c3f7..e9dea0bc42d0c99dc5b652af954aa0782c765e11 100644
--- a/third_party/WebKit/Source/core/editing/LayoutSelection.cpp
+++ b/third_party/WebKit/Source/core/editing/LayoutSelection.cpp
@@ -34,6 +34,7 @@ namespace blink {
 LayoutSelection::LayoutSelection(FrameSelection& frame_selection)
     : frame_selection_(&frame_selection),
       has_pending_selection_(false),
+      force_hide_(false),
       selection_start_(nullptr),
       selection_end_(nullptr),
       selection_start_pos_(-1),
@@ -111,6 +112,14 @@ SelectionInFlatTree LayoutSelection::CalcVisibleSelection(
   return builder.Build();
 }
 
+void LayoutSelection::SetHasPendingSelection(PaintHint hint) {
+  has_pending_selection_ = true;
+  if (hint == PaintHint::kHide)

[yosin_UTC9, 2017/04/13 09:31:50]

How about

if (hint == PaintHint::kKeep)
  return;
force_hide_ = hint == PaintHint::kHide;

[hugoh_UTC2, 2017/04/14 01:34:47]

Acknowledged. Semantically the same so this is a matter of taste. Hmm. :) I
think current logic is easier to read (no == operator to calculate).

[yosin_UTC9, 2017/04/14 02:29:16]

Blink prefers early-return style, though.

+    force_hide_ = true;
+  else if (hint == PaintHint::kPaint)
+    force_hide_ = false;
+}
+
 void LayoutSelection::Commit(LayoutView& layout_view) {
   if (!HasPendingSelection())
     return;
@@ -131,7 +140,7 @@ void LayoutSelection::Commit(LayoutView& layout_view) {
   const VisibleSelectionInFlatTree& selection =
       CreateVisibleSelection(CalcVisibleSelection(original_selection));
 
-  if (!selection.IsRange()) {
+  if (!selection.IsRange() || force_hide_) {
     ClearSelection();
     return;
   }
@@ -170,6 +179,7 @@ void LayoutSelection::Commit(LayoutView& layout_view) {
 
 void LayoutSelection::OnDocumentShutdown() {
   has_pending_selection_ = false;
+  force_hide_ = false;
   selection_start_ = nullptr;
   selection_end_ = nullptr;
   selection_start_pos_ = -1;