[Android] Support double-tap selection

ui/touch_selection/touch_selection_controller.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/touch_selection/touch_selection_controller.h"
 
 #include "base/auto_reset.h"
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 
@@ skipping 156 matching lines @@
     if ((event_pos - GetStartPosition()).LengthSquared() <=
         (event_pos - GetEndPosition()).LengthSquared()) {
       return start_selection_handle_->WillHandleTouchEvent(event);
     }
     return end_selection_handle_->WillHandleTouchEvent(event);
   }
 
   return false;
 }
 
-bool TouchSelectionController::WillHandleTapEvent(const gfx::PointF& location) {
+bool TouchSelectionController::WillHandleTapEvent(const gfx::PointF& location,
+                                                  int tap_count) {
   if (WillHandleTapOrLongPress(location))
     return true;
 
-  response_pending_input_event_ = TAP;
-  if (active_status_ != SELECTION_ACTIVE)
-    activate_selection_automatically_ = false;
+  if (tap_count > 1) {
+    response_pending_input_event_ = REPEATED_TAP;
+    ShowSelectionHandlesAutomatically();
+  } else {
+    response_pending_input_event_ = TAP;
+    if (active_status_ != SELECTION_ACTIVE)
+      activate_selection_automatically_ = false;
+  }
   ShowInsertionHandleAutomatically();
   if (selection_empty_ && !config_.show_on_tap_for_empty_editable)
     DeactivateInsertion();
   ForceNextUpdateIfInactive();
   return false;
 }
 
 bool TouchSelectionController::WillHandleLongPressEvent(
     base::TimeTicks event_time,
     const gfx::PointF& location) {
@@ skipping 227 matching lines @@
       RectFBetweenSelectionBounds(start_, end_).Contains(location)) {
     AllowShowingFromCurrentSelection();
     return true;
   }
   return false;
 }
 
 void TouchSelectionController::OnInsertionChanged() {
   DeactivateSelection();
 
-  if (response_pending_input_event_ == TAP && selection_empty_ &&
-      !config_.show_on_tap_for_empty_editable) {
+  if ((response_pending_input_event_ == TAP ||
+       response_pending_input_event_ == REPEATED_TAP) &&
+      selection_empty_ && !config_.show_on_tap_for_empty_editable) {
     HideAndDisallowShowingAutomatically();
     return;
   }
 
   if (!activate_insertion_automatically_)
     return;
 
   const bool activated = ActivateInsertionIfNecessary();
 
   const TouchHandle::AnimationStyle animation = GetAnimationStyle(!activated);
@@ skipping 62 matching lines @@
   } else {
     end_selection_handle_->SetEnabled(true);
     end_selection_handle_->SetOrientation(end_orientation_);
   }
 
   // As a long press received while a selection is already active may trigger
   // an entirely new selection, notify the client but avoid sending an
   // intervening SELECTION_HANDLES_CLEARED update to avoid unnecessary state
   // changes.
   if (active_status_ == INACTIVE ||
-      response_pending_input_event_ == LONG_PRESS) {
+      response_pending_input_event_ == LONG_PRESS ||
+      response_pending_input_event_ == REPEATED_TAP) {
     if (active_status_ == SELECTION_ACTIVE) {
       // The active selection session finishes with the start of the new one.
       LogSelectionEnd();
     }
     active_status_ = SELECTION_ACTIVE;
     selection_handle_dragged_ = false;
     selection_start_time_ = base::TimeTicks::Now();
     response_pending_input_event_ = INPUT_EVENT_TYPE_NONE;
     longpress_drag_selector_.OnSelectionActivated();
     return true;
@@ skipping 73 matching lines @@
     base::TimeDelta duration = base::TimeTicks::Now() - selection_start_time_;
     UMA_HISTOGRAM_CUSTOM_TIMES("Event.TouchSelection.WasDraggedDuration",
                                duration,
                                base::TimeDelta::FromMilliseconds(500),
                                base::TimeDelta::FromSeconds(60),
                                60);
   }
 }
 
 }  // namespace ui