Fixed Android text selection by redefining |button| value.

third_party/WebKit/public/platform/WebPointerProperties.h

 // Copyright (c) 2015 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.
 
 #ifndef WebPointerProperties_h
 #define WebPointerProperties_h
 
 #include <cstdint>
 #include <limits>
 
@@ skipping 62 matching lines @@
   // The normalized tangential pressure (or barrel pressure), typically set by
   // an additional control of the stylus, which has a range of [-1,1], where 0
   // is the neutral position of the control. Always 0 if the device does not
   // support it.
   float tangentialPressure;
 
   // The clockwise rotation of a pen stylus around its own major axis, in
   // degrees in the range [0,359]. Always 0 if the device does not support it.
   int twist;
 
+  // - For pointerup/down events, the button of pointing device that triggered
+  // the event.
+  // - For other events, the button that was depressed during the move event. If
+  // multiple buttons were depressed, one of the depressed buttons (platform
+  // dependent).
   Button button;
+
   PointerType pointerType;
 
   int movementX;
   int movementY;
 };
 
 }  // namespace blink
 
 #endif