The DisplayVirtualKeyboard function on Windows 8 and beyond should not be displaying the OSK if a p…

base/win/win_util.cc

Index: base/win/win_util.cc
diff --git a/base/win/win_util.cc b/base/win/win_util.cc
index 69e14e4f6aac04ca330890a177975e15dafc4039..ad18e702f3912c31cf89359da6253f163fe66a64 100644
--- a/base/win/win_util.cc
+++ b/base/win/win_util.cc
@@ -5,6 +5,7 @@
 #include "base/win/win_util.h"
 
 #include <aclapi.h>
+#include <cfgmgr32.h>
 #include <lm.h>
 #include <powrprof.h>
 #include <shellapi.h>
@@ -14,6 +15,7 @@
 #include <propkey.h>
 #include <propvarutil.h>
 #include <sddl.h>
+#include <setupapi.h>
 #include <signal.h>
 #include <stdlib.h>
 
@@ -53,6 +55,65 @@ const wchar_t kWindows8OSKRegPath[] =
     L"Software\\Classes\\CLSID\\{054AAE20-4BEA-4347-8A35-64A533254A9D}"
     L"\\LocalServer32";
 
+// Returns true if a physical keyboard is detected on Windows 8 and up.
+// Uses the Setup APIs to enumerate the attached keyboards and returns true
+// if the keyboard count is more than 1. While this will work in most cases
+// it won't work if there are devices which expose keyboard interfaces which
+// are attached to the machine.
+bool IsKeyboardPresent() {

[cpu_(ooo_6.6-7.5), 2014/10/16 18:11:33]

please rename this to IsKeyboardPresentOnSlate()  or .. OnTablet()

[ananta, 2014/10/16 19:35:58]

Done.

+  // This function is only supported for Windows 8 and up.
+  if (base::win::GetVersion() < base::win::VERSION_WIN8) {
+    DCHECK(false);
+    return true;
+  }
+
+  // This function should be only invoked for machines with touch screens.
+  if ((GetSystemMetrics(SM_DIGITIZER) & NID_INTEGRATED_TOUCH)
+        != NID_INTEGRATED_TOUCH) {
+    DCHECK(false);
+    return true;
+  }
+
+  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.
+  bool has_keyboard = false;

[scottmg, 2014/10/16 18:30:46]

this is unused

[ananta, 2014/10/16 19:35:58]

Done.

+  int32 keyboard_count = 0;

[scottmg, 2014/10/16 18:30:46]

just int

[ananta, 2014/10/16 19:35:58]

Done.

+  for (int 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;

[scottmg, 2014/10/16 18:30:46]

maybe continue?

[ananta, 2014/10/16 19:35:58]

The loop above continues indefinitely. That would need to change for continue.
leaving as is

+    // Get the device ID

[cpu_(ooo_6.6-7.5), 2014/10/16 18:11:33]

period at the end of comments.

[ananta, 2014/10/16 19:35:58]

Done.

+    WCHAR device_id[MAX_DEVICE_ID_LEN];

[cpu_(ooo_6.6-7.5), 2014/10/16 18:11:33]

WCHAR --> wchar_t

[ananta, 2014/10/16 19:35:58]

Done.

+    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 and HID
+      // keyboards.
+      if (!base::strncmp16(L"ACPI\\PNP", device_id, wcslen(L"ACPI\\PNP")) ||
+          !base::strncmp16(L"HID\\VID", device_id, wcslen(L"HID\\VID"))) {

[cpu_(ooo_6.6-7.5), 2014/10/16 18:11:33]

use StartsWith( and set it to be case insensitive?

[ananta, 2014/10/16 19:35:58]

Done.

+        keyboard_count++;
+      }
+    } else {
+      break;

[scottmg, 2014/10/16 18:30:46]

maybe no else to check any others?

[ananta, 2014/10/16 19:35:58]

Good point. Done.

+    }
+  }

[cpu_(ooo_6.6-7.5), 2014/10/16 18:11:33]

comment explaining why > 1.

[ananta, 2014/10/16 19:35:58]

Done.

+  return keyboard_count > 1;
+}
+
 }  // namespace
 
 namespace base {
@@ -252,6 +313,9 @@ bool DisplayVirtualKeyboard() {
   if (base::win::GetVersion() < base::win::VERSION_WIN8)
     return false;
 
+  if (IsKeyboardPresent())
+    return false;
+
   static base::LazyInstance<string16>::Leaky osk_path =
       LAZY_INSTANCE_INITIALIZER;