Ignore left-button eventSender.mouseDown() uses while dragging.

content/shell/renderer/test_runner/event_sender.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 "content/shell/renderer/test_runner/event_sender.h"
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
 #include "content/public/common/page_zoom.h"
@@ skipping 1171 matching lines @@
 
 void EventSender::MouseDown(int button_number, int modifiers) {
   if (force_layout_on_events_)
     view_->layout();
 
   DCHECK_NE(-1, button_number);
 
   WebMouseEvent::Button button_type =
       GetButtonTypeFromButtonNumber(button_number);
 
+  // Ignore invalid uses of mouseDown() while drag is in progress.
+  if (button_type == WebMouseEvent::ButtonLeft &&
+      !current_drag_data_.isNull())
+    return;
+
   UpdateClickCountForButton(button_type);
 
   pressed_button_ = button_type;
 
   WebMouseEvent event;
   InitMouseEvent(WebInputEvent::MouseDown,
                  button_type,
                  last_mouse_pos_,
                  GetCurrentEventTimeSec(),
                  click_count_,
@@ skipping 1134 matching lines @@
 
 bool EventSender::HandleInputEventOnViewOrPopup(const WebInputEvent& event) {
   if (WebPagePopup* popup = view_->pagePopup()) {
     if (!WebInputEvent::isKeyboardEventType(event.type))
       return popup->handleInputEvent(event);
   }
   return view_->handleInputEvent(event);
 }
 
 }  // namespace content