Limit visibility {Left,Right}BoundaryOfLine() to SelectionModifier only

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

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights
  * reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 19 matching lines @@
 #include "core/editing/Editor.h"
 #include "core/editing/VisibleUnits.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/layout/LayoutBlock.h"
 #include "core/layout/line/InlineTextBox.h"
 #include "core/page/SpatialNavigation.h"
 
 namespace blink {
 
+namespace {
+
+VisiblePosition LeftBoundaryOfLine(const VisiblePosition& c,
+                                   TextDirection direction) {
+  DCHECK(c.IsValid()) << c;
+  return direction == TextDirection::kLtr ? LogicalStartOfLine(c)
+                                          : LogicalEndOfLine(c);
+}
+
+VisiblePosition RightBoundaryOfLine(const VisiblePosition& c,
+                                    TextDirection direction) {
+  DCHECK(c.IsValid()) << c;
+  return direction == TextDirection::kLtr ? LogicalEndOfLine(c)
+                                          : LogicalStartOfLine(c);
+}
+
+}  // namespace
+
 LayoutUnit NoXPosForVerticalArrowNavigation() {
   return LayoutUnit::Min();
 }
 
 bool SelectionModifier::ShouldAlwaysUseDirectionalSelection(LocalFrame* frame) {
   return !frame ||
          frame->GetEditor().Behavior().ShouldConsiderSelectionAsDirectional();
 }
 
 SelectionModifier::SelectionModifier(
@@ skipping 793 matching lines @@
     x = LineDirectionPointForBlockDirectionNavigationOf(visible_position);
     x_pos_for_vertical_arrow_navigation_ = x;
   } else {
     x = x_pos_for_vertical_arrow_navigation_;
   }
 
   return x;
 }
 
 }  // namespace blink