views: support vertical-drag-to-end on textfields

ui/views/controls/textfield/textfield.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/textfield/textfield.h"
 
 #include <string>
 #include <utility>
 
 #include "base/trace_event/trace_event.h"
@@ skipping 22 matching lines @@
 #include "ui/views/background.h"
 #include "ui/views/controls/focusable_border.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/controls/menu/menu_runner.h"
 #include "ui/views/controls/native/native_view_host.h"
 #include "ui/views/controls/textfield/textfield_controller.h"
 #include "ui/views/drag_utils.h"
 #include "ui/views/metrics.h"
 #include "ui/views/native_cursor.h"
 #include "ui/views/painter.h"
+#include "ui/views/style/platform_style.h"
 #include "ui/views/views_delegate.h"
 #include "ui/views/widget/widget.h"
 
 #if defined(OS_WIN)
 #include "base/win/win_util.h"
 #endif
 
 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
 #include "base/strings/utf_string_conversions.h"
 #include "ui/events/linux/text_edit_command_auralinux.h"
@@ skipping 1686 matching lines @@
   canvas->Restore();
 }
 
 void Textfield::MoveCursorTo(const gfx::Point& point, bool select) {
   if (model_->MoveCursorTo(point, select))
     UpdateAfterChange(false, true);
 }
 
 void Textfield::SelectThroughLastDragLocation() {
   OnBeforeUserAction();
-  model_->MoveCursorTo(last_drag_location_, true);
+
+  const bool drags_to_end = PlatformStyle::kTextfieldDragVerticallyDragsToEnd;
+  if (drags_to_end && last_drag_location_.y() < 0) {
+    model_->MoveCursor(gfx::BreakType::LINE_BREAK,
+                       gfx::VisualCursorDirection::CURSOR_LEFT,
+                       true);

[tapted, 2016/04/11 06:57:26]

nit: git cl format puts this `true` on the previous line, same below

[Elly Fong-Jones, 2016/04/14 19:47:10]

Done.

+  } else if (drags_to_end && last_drag_location_.y() > height()) {
+    model_->MoveCursor(gfx::BreakType::LINE_BREAK,
+                       gfx::VisualCursorDirection::CURSOR_RIGHT,
+                       true);
+  } else {
+    model_->MoveCursorTo(last_drag_location_, true);
+  }
+
   if (aggregated_clicks_ == 1) {
     model_->SelectWord();
     // Expand the selection so the initially selected word remains selected.
     gfx::Range selection = GetRenderText()->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);
@@ skipping 141 matching lines @@
     RequestFocus();
   model_->MoveCursorTo(mouse);
   if (!selection_clipboard_text.empty()) {
     model_->InsertText(selection_clipboard_text);
     UpdateAfterChange(true, true);
   }
   OnAfterUserAction();
 }
 
 }  // namespace views