Validate that ui::Event::time_stamp comes from the same clock as TimeTicks::Now

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 1850 matching lines @@
       controller_->UpdateContextMenu(context_menu_contents_.get());
   }
   context_menu_runner_.reset(
       new MenuRunner(context_menu_contents_.get(),
                      MenuRunner::HAS_MNEMONICS | MenuRunner::CONTEXT_MENU));
 }
 
 void Textfield::TrackMouseClicks(const ui::MouseEvent& event) {
   if (event.IsOnlyLeftMouseButton()) {
     base::TimeDelta time_delta = event.time_stamp() - last_click_time_;
-    if (time_delta.InMilliseconds() <= GetDoubleClickInterval() &&
+    if (!last_click_time_.is_null() &&
+        time_delta.InMilliseconds() <= GetDoubleClickInterval() &&
         !ExceededDragThreshold(event.location() - last_click_location_)) {
       // Upon clicking after a triple click, the count should go back to double
       // click and alternate between double and triple. This assignment maps
       // 0 to 1, 1 to 2, 2 to 1.
       aggregated_clicks_ = (aggregated_clicks_ % 2) + 1;
     } else {
       aggregated_clicks_ = 0;
     }
     last_click_time_ = event.time_stamp();
     last_click_location_ = event.location();
@@ skipping 51 matching lines @@
     RequestFocus();
   model_->MoveCursorTo(mouse);
   if (!selection_clipboard_text.empty()) {
     model_->InsertText(selection_clipboard_text);
     UpdateAfterChange(true, true);
   }
   OnAfterUserAction();
 }
 
 }  // namespace views