RenderTextHarfBuzz: Add support for multi line text selection.

ui/views/selection_controller.cc

 // Copyright 2016 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/selection_controller.h"
 
 #include <algorithm>
 
 #include "ui/events/event.h"
 #include "ui/gfx/render_text.h"
@@ skipping 178 matching lines @@
 gfx::RenderText* SelectionController::GetRenderText() {
   return delegate_->GetRenderTextForSelectionController();
 }
 
 void SelectionController::SelectThroughLastDragLocation() {
   gfx::RenderText* render_text = GetRenderText();
   DCHECK(render_text);
 
   delegate_->OnBeforePointerAction();
 
-  // TODO(karandeepb): See if this can be handled at the RenderText level.
-  const bool drags_to_end = PlatformStyle::kTextDragVerticallyDragsToEnd;
-  if (drags_to_end && last_drag_location_.y() < 0) {
-    render_text->MoveCursor(gfx::LINE_BREAK, gfx::CURSOR_LEFT,
-                            gfx::SELECTION_RETAIN);
-  } else if (drags_to_end &&
-             last_drag_location_.y() > delegate_->GetViewHeight()) {
-    render_text->MoveCursor(gfx::LINE_BREAK, gfx::CURSOR_RIGHT,
-                            gfx::SELECTION_RETAIN);
-  } else {
-    render_text->MoveCursorTo(last_drag_location_, true);
-  }
+  render_text->MoveCursorTo(last_drag_location_, true);
 
   if (aggregated_clicks_ == 1) {
     render_text->SelectWord();
     // Expand the selection so the initially selected word remains selected.
     gfx::Range selection = render_text->selection();
     const size_t min =
         std::min(selection.GetMin(), double_click_word_.GetMin());
     const size_t max =
         std::max(selection.GetMax(), double_click_word_.GetMax());
     const bool reversed = selection.is_reversed();
     selection.set_start(reversed ? max : min);
     selection.set_end(reversed ? min : max);
     render_text->SelectRange(selection);
   }
   delegate_->OnAfterPointerAction(false, true);
 }
 
 }  // namespace views