Add support for horizontal mouse wheel messages in Windows Desktop Aura.

ui/events/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/events/event_constants.h"
 
 #include "base/logging.h"
 #include "base/time/time.h"
@@ skipping 162 matching lines @@
     case WM_NCRBUTTONUP:
     case WM_NCXBUTTONUP:
     case WM_RBUTTONUP:
     case WM_XBUTTONUP:
       return ET_MOUSE_RELEASED;
     case WM_MOUSEMOVE:
       return IsButtonDown(native_event) ? ET_MOUSE_DRAGGED : ET_MOUSE_MOVED;
     case WM_NCMOUSEMOVE:
       return ET_MOUSE_MOVED;
     case WM_MOUSEWHEEL:
+    case WM_MOUSEHWHEEL:
       return ET_MOUSEWHEEL;
     case WM_MOUSELEAVE:
     case WM_NCMOUSELEAVE:
       return ET_MOUSE_EXITED;
     case WM_VSCROLL:
     case WM_HSCROLL:
       return ET_SCROLL;
     default:
       // We can't NOTREACHED() here, since this function can be called for any
       // message.
@@ skipping 68 matching lines @@
     case MK_RBUTTON:
       return EF_RIGHT_MOUSE_BUTTON;
     // TODO: add support for MK_XBUTTON1.
     default:
       break;
   }
   return 0;
 }
 
 gfx::Vector2d GetMouseWheelOffset(const base::NativeEvent& native_event) {
-  DCHECK(native_event.message == WM_MOUSEWHEEL);
+  DCHECK(native_event.message == WM_MOUSEWHEEL ||
+         native_event.message == WM_MOUSEHWHEEL);
   return gfx::Vector2d(0, GET_WHEEL_DELTA_WPARAM(native_event.wParam));

[sky, 2014/01/17 00:35:18]

WOuldn't a horizontal scroll effect the first parameter?

[ananta, 2014/01/17 00:47:17]

Doh. Should have seen that. Works in desktop Chrome on a page because RVHA uses
the native event to construct the wheel information.

Done.

 }
 
 void ClearTouchIdIfReleased(const base::NativeEvent& xev) {
   NOTIMPLEMENTED();
 }
 
 int GetTouchId(const base::NativeEvent& xev) {
   NOTIMPLEMENTED();
   return 0;
 }
@@ skipping 124 matching lines @@
 }
 
 LPARAM GetLParamFromScanCode(uint16 scan_code) {
   LPARAM l_param = static_cast<LPARAM>(scan_code & 0x00FF) << 16;
   if ((scan_code & 0xE000) == 0xE000)
     l_param |= (1 << 24);
   return l_param;
 }
 
 }  // namespace ui