Set the unique_event_id when converting from TouchEvent to WebTouchEvent

ui/events/event.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/events/event.h"
 
 #if defined(USE_X11)
 #include <X11/extensions/XInput2.h>
 #include <X11/keysym.h>
 #include <X11/Xlib.h>
@@ skipping 92 matching lines @@
   const unsigned int kAllStateMask =
       Button1Mask | Button2Mask | Button3Mask | Button4Mask | Button5Mask |
       Mod1Mask | Mod2Mask | Mod3Mask | Mod4Mask | Mod5Mask | ShiftMask |
       LockMask | ControlMask | AnyModifier;
   return event && (event->xkey.state & ~kAllStateMask) != 0;
 #else
   return false;
 #endif
 }
 
-unsigned long long get_next_touch_event_id() {
-  static unsigned long long id = 0;
+uint64 get_next_touch_event_id() {
+  // Set the first touch_event_id to 1 because we set id to 0 for other types
+  // of events.
+  static uint64 id = 1;
+  if (id==0)
+    id++;
+  DCHECK_NE(id, 0UL);
   return id++;
 }
 
 }  // namespace
 
 namespace ui {
 
 ////////////////////////////////////////////////////////////////////////////////
 // Event
 
@@ skipping 859 matching lines @@
                    gfx::PointF(x, y),
                    time_stamp,
                    flags | EF_FROM_TOUCH),
       details_(details) {
 }
 
 GestureEvent::~GestureEvent() {
 }
 
 }  // namespace ui