Widen the keyboard detection logic on Windows 8 touch devices and detect slate mode to force OSK on.

base/win/win_util.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 "base/win/win_util.h"
 
 #include <aclapi.h>
 #include <cfgmgr32.h>
 #include <lm.h>
 #include <powrprof.h>
@@ skipping 52 matching lines @@
 bool IsKeyboardPresentOnSlate() {
   // This function is only supported for Windows 8 and up.
   DCHECK(base::win::GetVersion() >= base::win::VERSION_WIN8);
 
   // This function should be only invoked for machines with touch screens.
   if ((GetSystemMetrics(SM_DIGITIZER) & NID_INTEGRATED_TOUCH)
         != NID_INTEGRATED_TOUCH) {
     return true;
   }
 
+  // If the device is docked, the user is treating the device as a PC.
+  if (GetSystemMetrics(SM_SYSTEMDOCKED) != 0)
+    return true;
+
+  // To determine whether a keyboard is present on the device, we do the
+  // following:-
+  // 1. Check whether the device supports auto rotation. If it does then
+  //    it possibly supports flipping from laptop to slate mode. If it
+  //    does not support auto rotation, then we assume it is a desktop
+  //    or a normal laptop and assume that there is a keyboard.
+
+  // 2. If the device supports auto rotation, then we get its platform role
+  //    and check the system metric SM_CONVERTIBLESLATEMODE to see if it is
+  //    being used in slate mode. If yes then we return false here to ensure
+  //    that the OSK is displayed.
+
+  // 3. If step 1 and 2 fail then we check attached keyboards and return true
+  //    if we find ACPI\* or HID\VID* keyboards.
+
+  typedef BOOL (WINAPI* GetAutoRotationState)(PAR_STATE state);
+
+  GetAutoRotationState get_rotation_state =
+      reinterpret_cast<GetAutoRotationState>(::GetProcAddress(
+          GetModuleHandle(L"user32.dll"), "GetAutoRotationState"));
+
+  if (get_rotation_state) {
+    AR_STATE auto_rotation_state = AR_ENABLED;
+    get_rotation_state(&auto_rotation_state);
+    if ((auto_rotation_state & AR_NOSENSOR) ||
+        (auto_rotation_state & AR_NOT_SUPPORTED)) {
+      // If there is no auto rotation sensor or rotation is not supported in
+      // the current configuration, then we can assume that this is a desktop
+      // or a traditional laptop.
+      return true;
+    }
+  }
+
+  // Check if the device is being used as a laptop or a tablet. This can be
+  // checked by first checking the role of the device and then the
+  // corresponding system metric (SM_CONVERTIBLESLATEMODE). If it is being used
+  // as a tablet then we want the OSK to show up.
+  POWER_PLATFORM_ROLE role = PowerDeterminePlatformRole();

[cpu_(ooo_6.6-7.5), 2015/03/09 20:30:05]

is PowerDeterminePlatformRole() delay loaded?  does not exist in xp.

[ananta, 2015/03/10 02:00:58]

The IsTabletDevice function calls this API today. In any case this function
should be invoked on Windows 8+

+
+  if (((role == PlatformRoleMobile) || (role == PlatformRoleSlate)) &&
+       (GetSystemMetrics(SM_CONVERTIBLESLATEMODE) == 0))
+    return false;
+
   const GUID KEYBOARD_CLASS_GUID =
       { 0x4D36E96B, 0xE325,  0x11CE,
           { 0xBF, 0xC1, 0x08, 0x00, 0x2B, 0xE1, 0x03, 0x18 } };
 
   // Query for all the keyboard devices.
   HDEVINFO device_info =
       SetupDiGetClassDevs(&KEYBOARD_CLASS_GUID, NULL, NULL, DIGCF_PRESENT);
   if (device_info == INVALID_HANDLE_VALUE)
     return false;
 
   // Enumerate all keyboards and look for ACPI\PNP and HID\VID devices. If
   // the count is more than 1 we assume that a keyboard is present. This is
   // under the assumption that there will always be one keyboard device.
   int keyboard_count = 0;
   for (DWORD i = 0;; ++i) {
     SP_DEVINFO_DATA device_info_data = { 0 };
     device_info_data.cbSize = sizeof(device_info_data);
     if (!SetupDiEnumDeviceInfo(device_info, i, &device_info_data))
       break;
 
     // Get the device ID.
     wchar_t device_id[MAX_DEVICE_ID_LEN];
     CONFIGRET status = CM_Get_Device_ID(device_info_data.DevInst,
                                         device_id,
                                         MAX_DEVICE_ID_LEN,
                                         0);
     if (status == CR_SUCCESS) {
-      // To reduce the scope of the hack we only look for PNP, MSF and HID
-      // keyboards.
-      if (StartsWith(device_id, L"ACPI\\PNP", false) ||
-          StartsWith(device_id, L"ACPI\\MSF", false) ||
+      // To reduce the scope of the hack we only look for ACPI and HID\\VID
+      // prefixes in the keyboard device ids.
+      if (StartsWith(device_id, L"ACPI", false) ||
           StartsWith(device_id, L"HID\\VID", false)) {
         keyboard_count++;
       }
     }
   }
   // The heuristic we are using is to check the count of keyboards and return
   // true if the API's report one or more keyboards. Please note that this
   // will break for non keyboard devices which expose a keyboard PDO.
   return keyboard_count >= 1;
 }
@@ skipping 327 matching lines @@
   // deployed.
   if (os_info->version() == base::win::VERSION_SERVER_2003)
     return false;
 
   DCHECK(os_info->version() >= base::win::VERSION_VISTA);
   return true;  // New enough to have SHA-256 support.
 }
 
 }  // namespace win
 }  // namespace base