Correct behaviour of touch wrt mouse capture.

ui/base/win/events_win.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 <windowsx.h>
 
 #include "ui/base/events.h"
 
 #include "base/logging.h"
 #include "base/time.h"
 #include "base/win/win_util.h"
 #include "ui/base/keycodes/keyboard_code_conversion_win.h"
 #include "ui/gfx/point.h"
 
 namespace {
 
+// From MSDN.
+#define MOUSEEVENTF_FROMTOUCH 0xFF515700
+
 // Get the native mouse key state from the native event message type.
 int GetNativeMouseKey(const base::NativeEvent& native_event) {
   switch (native_event.message) {
     case WM_LBUTTONDBLCLK:
     case WM_LBUTTONDOWN:
     case WM_LBUTTONUP:
     case WM_NCLBUTTONDBLCLK:
     case WM_NCLBUTTONDOWN:
     case WM_NCLBUTTONUP:
       return MK_LBUTTON;
@@ skipping 278 matching lines @@
   int modifiers = ui::EF_NONE;
   if (accel.fVirt & FSHIFT)
     modifiers |= ui::EF_SHIFT_DOWN;
   if (accel.fVirt & FCONTROL)
     modifiers |= ui::EF_CONTROL_DOWN;
   if (accel.fVirt & FALT)
     modifiers |= ui::EF_ALT_DOWN;
   return modifiers;
 }
 
+// Windows emulates mouse messages for touch events.
+bool IsMouseEventFromTouch(UINT message) {
+  return (message == WM_MOUSEMOVE ||
+      message == WM_LBUTTONDOWN || message == WM_LBUTTONUP ||
+      message == WM_RBUTTONDOWN || message == WM_RBUTTONUP) &&
+      (GetMessageExtraInfo() & MOUSEEVENTF_FROMTOUCH) ==
+      MOUSEEVENTF_FROMTOUCH;
+}
+
 }  // namespace ui