MacViews: Tweak kDragToEndIfOutsideVerticalBounds for single line fields.

ui/gfx/render_text_harfbuzz.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/render_text_harfbuzz.h"
 
 #include <limits>
 #include <set>
 
 #include "base/command_line.h"
@@ skipping 878 matching lines @@
 SizeF RenderTextHarfBuzz::GetStringSizeF() {
   EnsureLayout();
   return total_size_;
 }
 
 SelectionModel RenderTextHarfBuzz::FindCursorPosition(const Point& view_point) {
   EnsureLayout();
   DCHECK(!lines().empty());
 
   int line_index = GetLineContainingYCoord((view_point - GetLineOffset(0)).y());
-  // Clip line index to a valid value in case kDragToEndIfOutsideVerticalBounds
-  // is false. Else, drag to end.
+  // Handle kDragToEndIfOutsideVerticalBounds above or below the text in a
+  // single-line by extending towards the mouse cursor.
+  if (RenderText::kDragToEndIfOutsideVerticalBounds && !multiline() &&
+      (line_index < 0 || line_index >= static_cast<int>(lines().size()))) {
+    SelectionModel selection_start = GetSelectionModelForSelectionStart();
+    bool left = view_point.x() < GetCursorBounds(selection_start, true).x();
+    return EdgeSelectionModel(left ? CURSOR_LEFT : CURSOR_RIGHT);
+  }
+  // Otherwise, clamp |line_index| to a valid value or drag to logical ends.
   if (line_index < 0) {
     if (RenderText::kDragToEndIfOutsideVerticalBounds)
       return EdgeSelectionModel(GetVisualDirectionOfLogicalBeginning());
-    else
-      line_index = 0;
+    line_index = 0;
   }
   if (line_index >= static_cast<int>(lines().size())) {
     if (RenderText::kDragToEndIfOutsideVerticalBounds)
       return EdgeSelectionModel(GetVisualDirectionOfLogicalEnd());
-    else
-      line_index = lines().size() - 1;
+    line_index = lines().size() - 1;
   }
   const internal::Line& line = lines()[line_index];
 
   float point_offset_relative_segment = 0;
   const int segment_index = GetLineSegmentContainingXCoord(
       line, (view_point - GetLineOffset(line_index)).x(),
       &point_offset_relative_segment);
   if (segment_index < 0)
     return LineSelectionModel(line_index, CURSOR_LEFT);
   if (segment_index >= static_cast<int>(line.segments.size()))
@@ skipping 804 matching lines @@
 
       attribute.strike = run.strike;
       attribute.diagonal_strike = run.diagonal_strike;
       decorated_text->attributes.push_back(attribute);
     }
   }
   return true;
 }
 
 }  // namespace gfx