Introduce VisibleSelection::CreateWithoutValidationDeprecated()

This patch introduces |VisibleSelection::CreateWithoutValidationDeprecated()|
as replacement of |SetWithoutValidation()| to make |VisibleSelection| as
virtually immutable for improving code health.

BUG=660320
TEST=n/a; no behavior changes

Review-Url: https://codereview.chromium.org/2952973002
Cr-Commit-Position: refs/heads/master@{#481799}

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

@@ -473,32 +473,36 @@ bool VisibleSelectionTemplate<Strategy>::IsValidFor(
 // |VisibleSelection| or create a new class for editing to use that can
 // manipulate selections that are not currently valid.
 template <typename Strategy>
-void VisibleSelectionTemplate<Strategy>::SetWithoutValidation(
+VisibleSelectionTemplate<Strategy>
+VisibleSelectionTemplate<Strategy>::CreateWithoutValidationDeprecated(
     const PositionTemplate<Strategy>& base,
-    const PositionTemplate<Strategy>& extent) {
-  if (base.IsNull() || extent.IsNull()) {
-    base_ = extent_ = start_ = end_ = PositionTemplate<Strategy>();
-    UpdateSelectionType();
-    return;
-  }
-
-  base_ = base;
-  extent_ = extent;
-  base_is_first_ = base.CompareTo(extent) <= 0;
-  if (base_is_first_) {
-    start_ = base;
-    end_ = extent;
+    const PositionTemplate<Strategy>& extent,
+    TextAffinity affinity) {
+  DCHECK(base.IsNotNull());
+  DCHECK(extent.IsNotNull());
+
+  VisibleSelectionTemplate<Strategy> visible_selection;
+  visible_selection.base_ = base;
+  visible_selection.extent_ = extent;
+  visible_selection.base_is_first_ = base.CompareTo(extent) <= 0;
+  if (visible_selection.base_is_first_) {
+    visible_selection.start_ = base;
+    visible_selection.end_ = extent;
   } else {
-    start_ = extent;
-    end_ = base;
+    visible_selection.start_ = extent;
+    visible_selection.end_ = base;
   }
-  selection_type_ = base == extent ? kCaretSelection : kRangeSelection;
-  if (selection_type_ != kCaretSelection) {
-    // Since |m_affinity| for non-|CaretSelection| is always |Downstream|,
-    // we should keep this invariant. Note: This function can be called with
-    // |m_affinity| is |TextAffinity::Upstream|.
-    affinity_ = TextAffinity::kDownstream;
+  if (base == extent) {
+    visible_selection.selection_type_ = kCaretSelection;
+    visible_selection.affinity_ = affinity;
+    return visible_selection;
   }
+  // Since |affinity_| for non-|CaretSelection| is always |kDownstream|,
+  // we should keep this invariant. Note: This function can be called with
+  // |affinity_| is |kUpstream|.
+  visible_selection.selection_type_ = kRangeSelection;
+  visible_selection.affinity_ = TextAffinity::kDownstream;
+  return visible_selection;
 }
 
 template <typename Strategy>

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

@@ -125,8 +125,14 @@ class CORE_TEMPLATE_CLASS_EXPORT VisibleSelectionTemplate {
   bool IsContentRichlyEditable() const;
 
   bool IsValidFor(const Document&) const;
-  void SetWithoutValidation(const PositionTemplate<Strategy>&,
-                            const PositionTemplate<Strategy>&);
+
+  // TODO(editing-dev): |CreateWithoutValidationDeprecated()| is allowed
+  // only to use in |TypingCommand| to remove part of grapheme cluster.
+  // Note: |base| and |extent| can be disconnect position.
+  static VisibleSelectionTemplate<Strategy> CreateWithoutValidationDeprecated(
+      const PositionTemplate<Strategy>& base,
+      const PositionTemplate<Strategy>& extent,
+      TextAffinity);
 
   DECLARE_TRACE();
 

third_party/WebKit/Source/core/editing/commands/TypingCommand.cpp

@@ -809,10 +809,12 @@ void TypingCommand::DeleteKeyPressed(TextGranularity granularity,
               1) {
         // If there are multiple Unicode code points to be deleted, adjust the
         // range to match platform conventions.
-        selection_to_delete.SetWithoutValidation(
+        selection_to_delete =
+            VisibleSelection::CreateWithoutValidationDeprecated(
                 selection_to_delete.End(),
                 PreviousPositionOf(selection_to_delete.End(),
-                               PositionMoveType::kBackwardDeletion));
+                                   PositionMoveType::kBackwardDeletion),
+                selection_to_delete.Affinity());
       }
 
       if (!StartingSelection().IsRange() ||
@@ -823,8 +825,10 @@ void TypingCommand::DeleteKeyPressed(TextGranularity granularity,
         // have been in the original document. We can't let the VisibleSelection
         // class's validation kick in or it'll adjust for us based on the
         // current state of the document and we'll get the wrong result.
-        selection_after_undo.SetWithoutValidation(StartingSelection().End(),
-                                                  selection_to_delete.Extent());
+        selection_after_undo =
+            VisibleSelection::CreateWithoutValidationDeprecated(
+                StartingSelection().End(), selection_to_delete.Extent(),
+                selection_after_undo.Affinity());
       }
       break;
     }
@@ -955,8 +959,10 @@ void TypingCommand::ForwardDeleteKeyPressed(TextGranularity granularity,
               extent.ComputeContainerNode(),
               extent.ComputeOffsetInContainerNode() + extra_characters);
         }
-        selection_after_undo.SetWithoutValidation(StartingSelection().Start(),
-                                                  extent);
+        selection_after_undo =
+            VisibleSelection::CreateWithoutValidationDeprecated(
+                StartingSelection().Start(), extent,
+                selection_after_undo.Affinity());
       }
       break;
     }