RenderTextHarfBuzz: Add support for multi line text selection.

ui/views/controls/label.cc

 // Copyright (c) 2012 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/views/controls/label.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <cmath>
@@ skipping 157 matching lines @@
 void Label::SetMultiLine(bool multi_line) {
   DCHECK(!multi_line || (elide_behavior_ == gfx::ELIDE_TAIL ||
                          elide_behavior_ == gfx::NO_ELIDE));
   if (this->multi_line() == multi_line)
     return;
   is_first_paint_text_ = true;
   multi_line_ = multi_line;
   if (render_text_->MultilineSupported())
     render_text_->SetMultiline(multi_line);
   render_text_->SetReplaceNewlineCharsWithSymbols(!multi_line);
-  if (multi_line)
-    SetSelectable(false);
   ResetLayout();
 }
 
 void Label::SetObscured(bool obscured) {
   if (this->obscured() == obscured)
     return;
   is_first_paint_text_ = true;
   render_text_->SetObscured(obscured);
   if (obscured)
     SetSelectable(false);
@@ skipping 53 matching lines @@
     return result;
   result.append(lines_[0]->GetDisplayText());
   for (size_t i = 1; i < lines_.size(); ++i) {
     result.append(1, '\n');
     result.append(lines_[i]->GetDisplayText());
   }
   return result;
 }
 
 bool Label::IsSelectionSupported() const {
-  return !multi_line() && !obscured() && render_text_->IsSelectionSupported();
+  return !obscured() && render_text_->IsSelectionSupported();
 }
 
 bool Label::SetSelectable(bool value) {
   if (value == selectable())
     return true;
 
   if (!value) {
     ClearSelection();
     stored_selection_range_ = gfx::Range::InvalidRange();
     selection_controller_.reset();
@@ skipping 752 matching lines @@
       .WriteText(GetSelectedText());
 }
 
 void Label::BuildContextMenuContents() {
   context_menu_contents_.AddItemWithStringId(IDS_APP_COPY, IDS_APP_COPY);
   context_menu_contents_.AddItemWithStringId(IDS_APP_SELECT_ALL,
                                              IDS_APP_SELECT_ALL);
 }
 
 }  // namespace views