Check for valid file handle on gamepads

Windows sometimes keeps a cache of gamepads that are not plugged into
the machine.  To distinguish between gamepads we can talk to and
gamepads we cannot this CL adds a check for a valid file handle.  If
Windows does not return a valid file handle we do not take up a slot
for that gamepad.

Bug: 985446
Change-Id: I2bf917bd8989e9238128426af9b804627446c2eb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1768878
Commit-Queue: James Hollyer <jameshollyer@chromium.org>
Reviewed-by: Matt Reynolds <mattreynolds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#691285}

device/gamepad/raw_input_gamepad_device_win.cc

@@ -263,8 +263,15 @@ bool RawInputGamepadDeviceWin::QueryDeviceInfo() {
   if (name_ == L"\\\\?\\VIRTUAL_DIGITIZER")
     return false;
 
+  // We can now use the name to query the OS for a file handle that is used to
+  // read the product string from the device. If the OS does not return a valid
+  // handle this gamepad is invalid.
+  auto hid_handle = OpenHidHandle();
+  if (!hid_handle.IsValid())
+    return false;
+
   // Fetch the human-friendly |product_string_|, if available.
-  if (!QueryProductString())
+  if (!QueryProductString(hid_handle))
     product_string_ = L"Unknown Gamepad";
 
   // Fetch information about the buttons and axes on this device. This sets
@@ -336,19 +343,21 @@ bool RawInputGamepadDeviceWin::QueryDeviceName() {
   return true;
 }
 
-bool RawInputGamepadDeviceWin::QueryProductString() {
-  DCHECK(hid_functions_);
-  DCHECK(hid_functions_->IsValid());
-  base::win::ScopedHandle hid_handle(::CreateFile(
-      name_.c_str(), GENERIC_READ | GENERIC_WRITE,
-      FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, NULL, NULL));
-  if (!hid_handle.IsValid())
-    return false;
+bool RawInputGamepadDeviceWin::QueryProductString(
+    base::win::ScopedHandle& hid_handle) {
+  DCHECK(hid_handle.IsValid());
   product_string_.resize(Gamepad::kIdLengthCap);
   return hid_functions_->HidDGetProductString()(
       hid_handle.Get(), &product_string_.front(), Gamepad::kIdLengthCap);
 }
 
+base::win::ScopedHandle RawInputGamepadDeviceWin::OpenHidHandle() {
+  return base::win::ScopedHandle(::CreateFile(
+      name_.c_str(), GENERIC_READ | GENERIC_WRITE,
+      FILE_SHARE_READ | FILE_SHARE_WRITE, /*lpSecurityAttributes=*/nullptr,
+      OPEN_EXISTING, /*dwFlagsAndAttributes=*/0, /*hTemplateFile=*/nullptr));
+}
+
 bool RawInputGamepadDeviceWin::QueryDeviceCapabilities() {
   DCHECK(hid_functions_);
   DCHECK(hid_functions_->IsValid());

device/gamepad/raw_input_gamepad_device_win.h

@@ -75,6 +75,10 @@ class RawInputGamepadDeviceWin final : public AbstractHapticGamepad {
   // AbstractHapticGamepad implementation.
   void DoShutdown() override;
 
+  // "Returns an open handle for the HID device, or an invalid handle if the
+  // device could not be opened."
+  base::win::ScopedHandle OpenHidHandle();
+
   // Fetch information about this device. Returns true if the device appears to
   // be a valid gamepad.
   bool QueryDeviceInfo();
@@ -86,7 +90,7 @@ class RawInputGamepadDeviceWin final : public AbstractHapticGamepad {
   bool QueryDeviceName();
 
   // Fetch the product string. Returns false if none is available.
-  bool QueryProductString();
+  bool QueryProductString(base::win::ScopedHandle& hid_handle);
 
   // These methods fetch information about the capabilities of buttons and axes
   // on the device.