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

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

Index: third_party/WebKit/Source/core/editing/FrameSelection.h
diff --git a/third_party/WebKit/Source/core/editing/FrameSelection.h b/third_party/WebKit/Source/core/editing/FrameSelection.h
index 8720d8789d9fe7f7d410aaac75af3fe7f0850420..79788802f696852f2ec4f3f45aa6d59a674c2681 100644
--- a/third_party/WebKit/Source/core/editing/FrameSelection.h
+++ b/third_party/WebKit/Source/core/editing/FrameSelection.h
@@ -32,7 +32,6 @@
 #include "core/dom/Range.h"
 #include "core/dom/SynchronousMutationObserver.h"
 #include "core/editing/EphemeralRange.h"
-#include "core/editing/LayoutSelection.h"
 #include "core/editing/VisiblePosition.h"
 #include "core/editing/VisibleSelection.h"
 #include "core/editing/iterators/TextIteratorBehavior.h"
@@ -131,6 +130,7 @@ class CORE_EXPORT FrameSelection final
       FrameSelection::SetSelectionOptions = kCloseTyping | kClearTypingStyle);
   void SelectAll();
   void Clear();
+  bool IsActive() const;

[Xiaocheng, 2017/05/02 20:05:17]

"Active" is a heavily overloaded term.

Judging from the unit tests related to range selection in contenteditable div,
it seems that this function only determines if the selection (caret or range)
should be painted or not. If so, could you make it clear?

[hugoh_UTC2, 2017/05/03 07:18:55]

It is not only used for deciding if a selection is painted or not. As yosin@
pointed out, "even if we don't paint selection, selection is still available".

 
   // TODO(tkent): These two functions were added to fix crbug.com/695211 without
   // changing focus behavior. Once we fix crbug.com/690272, we can remove these
@@ -242,7 +242,7 @@ class CORE_EXPORT FrameSelection final
       RevealExtentOption = kDoNotRevealExtent);
   void SetSelectionFromNone();
 
-  void UpdateAppearance(LayoutSelection::PaintHint);
+  void UpdateAppearance();
   bool ShouldShowBlockCursor() const;
   void SetShouldShowBlockCursor(bool);
 
@@ -308,7 +308,6 @@ class CORE_EXPORT FrameSelection final
 
   const Member<FrameCaret> frame_caret_;
   bool use_secure_keyboard_entry_when_active_ = false;
-  bool text_control_focused_ = false;
 };
 
 }  // namespace blink