Ensure that trackpad and trackpoint scrolling works on Windows desktop Aura with legacy trackpad dr…

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 72 matching lines @@
 }
 
 bool IsKeyEvent(const base::NativeEvent& native_event) {
   return native_event.message == WM_KEYDOWN ||
          native_event.message == WM_SYSKEYDOWN ||
          native_event.message == WM_CHAR ||
          native_event.message == WM_KEYUP ||
          native_event.message == WM_SYSKEYUP;
 }
 
+bool IsScrollEvent(const base::NativeEvent& native_event) {
+  return native_event.message == WM_VSCROLL ||
+         native_event.message == WM_HSCROLL;
+}
+
 // Returns a mask corresponding to the set of pressed modifier keys.
 // Checks the current global state and the state sent by client mouse messages.
 int KeyStateFlagsFromNative(const base::NativeEvent& native_event) {
   int flags = 0;
   flags |= base::win::IsAltPressed() ? EF_ALT_DOWN : EF_NONE;
   flags |= base::win::IsShiftPressed() ? EF_SHIFT_DOWN : EF_NONE;
   flags |= base::win::IsCtrlPressed() ? EF_CONTROL_DOWN : EF_NONE;
 
   // Check key messages for the extended key flag.
   if (IsKeyEvent(native_event))
@@ skipping 69 matching lines @@
       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:
       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.
       break;
   }
   return ET_UNKNOWN;
 }
 
 int EventFlagsFromNative(const base::NativeEvent& native_event) {
   int flags = KeyStateFlagsFromNative(native_event);
   if (IsMouseEvent(native_event))
     flags |= MouseStateFlagsFromNative(native_event);
 
   return flags;
 }
 
 base::TimeDelta EventTimeFromNative(const base::NativeEvent& native_event) {
   return base::TimeDelta::FromMilliseconds(native_event.time);
 }
 
 gfx::Point EventLocationFromNative(const base::NativeEvent& native_event) {
   // Note: Wheel events are considered client, but their position is in screen
   //       coordinates.
   // Client message. The position is contained in the LPARAM.
   if (IsClientMouseEvent(native_event) && !IsMouseWheelEvent(native_event))
     return gfx::Point(native_event.lParam);
   DCHECK(IsNonClientMouseEvent(native_event) ||
-         IsMouseWheelEvent(native_event));
-  // Non-client message. The position is contained in a POINTS structure in
-  // LPARAM, and is in screen coordinates so we have to convert to client.
-  POINT native_point = { GET_X_LPARAM(native_event.lParam),
-                         GET_Y_LPARAM(native_event.lParam) };
+         IsMouseWheelEvent(native_event) || IsScrollEvent(native_event));
+  POINT native_point;
+  if (IsScrollEvent(native_event)) {
+    ::GetCursorPos(&native_point);
+  } else {
+    // Non-client message. The position is contained in a POINTS structure in
+    // LPARAM, and is in screen coordinates so we have to convert to client.
+    native_point.x = GET_X_LPARAM(native_event.lParam);
+    native_point.y = GET_Y_LPARAM(native_event.lParam);
+  }
   ScreenToClient(native_event.hwnd, &native_point);
   gfx::Point location(native_point);
   location = gfx::win::ScreenToDIPPoint(location);
   return location;
 }
 
 gfx::Point EventSystemLocationFromNative(
     const base::NativeEvent& native_event) {
   // TODO(ben): Needs to always return screen position here. Returning normal
   // origin for now since that's obviously wrong.
@@ skipping 63 matching lines @@
   NOTIMPLEMENTED();
   return 0.0;
 }
 
 bool GetScrollOffsets(const base::NativeEvent& native_event,
                       float* x_offset,
                       float* y_offset,
                       float* x_offset_ordinal,
                       float* y_offset_ordinal,
                       int* finger_count) {
-  // Not supported in Windows.
-  NOTIMPLEMENTED();
+  // TODO(ananta)
+  // Support retrieving the scroll offsets from the scroll event.
+  if (native_event.message == WM_VSCROLL || native_event.message == WM_HSCROLL)
+    return true;
   return false;
 }
 
 bool GetFlingData(const base::NativeEvent& native_event,
                   float* vx,
                   float* vy,
                   float* vx_ordinal,
                   float* vy_ordinal,
                   bool* is_cancel) {
   // Not supported in Windows.
@@ skipping 83 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