Revert "Use UdevWatcher to filter USB, HID and serial devices"

This reverts commit 35f83455.

Reason for revert: This appears to be tickling a udev bug which causes crbug/1121007.

Original change's description:
> Use UdevWatcher to filter USB, HID and serial devices
>
> UsbServiceLinux, HidServiceLinux and SerialDeviceEnumeratorLinux each
> only care about devices from a particular subsystem. This change avoids
> processing other devices which should decrease the time it takes to
> perform the initial enumeration.
>
> Change-Id: I3535b5e6ecbb8c013957197cff151011a19a6097
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2227094
> Commit-Queue: Reilly Grant <reillyg@chromium.org>
> Commit-Queue: Matt Reynolds <mattreynolds@chromium.org>
> Reviewed-by: Matt Reynolds <mattreynolds@chromium.org>
> Auto-Submit: Reilly Grant <reillyg@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#774416}

Bug: 1121007
Change-Id: Ic6a69eb2bf3825ecbc9cb310bc71eb37d647d1c8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2429232Reviewed-by: Ken Rockot <rockot@google.com>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Commit-Queue: Reilly Grant <reillyg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810868}

services/device/hid/hid_service_linux.cc

@@ -205,8 +205,7 @@ class HidServiceLinux::BlockingTaskRunnerHelper : public UdevWatcher::Observer {
   void Start() {
     DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
-    watcher_ = UdevWatcher::StartWatching(
-        this, {UdevWatcher::Filter(kSubsystemHidraw, "")});
+    watcher_ = UdevWatcher::StartWatching(this);
     watcher_->EnumerateExistingDevices();
     task_runner_->PostTask(
         FROM_HERE,
@@ -225,11 +224,9 @@ class HidServiceLinux::BlockingTaskRunnerHelper : public UdevWatcher::Observer {
       return;
     HidPlatformDeviceId platform_device_id = device_path;
 
-#if DCHECK_IS_ON()
     const char* subsystem = udev_device_get_subsystem(device.get());
-    DCHECK(subsystem);
-    DCHECK_EQ(base::StringPiece(subsystem), kSubsystemHidraw);
-#endif
+    if (!subsystem || strcmp(subsystem, kSubsystemHidraw) != 0)
+      return;
 
     const char* str_property = udev_device_get_devnode(device.get());
     if (!str_property)

services/device/serial/serial_device_enumerator_linux.cc

@@ -23,8 +23,6 @@ namespace device {
 
 namespace {
 
-constexpr char kSubsystemTty[] = "tty";
-
 // Holds information about a TTY driver for serial devices. Each driver creates
 // device nodes with a given major number and in a range of minor numbers.
 struct SerialDriverInfo {
@@ -95,8 +93,7 @@ SerialDeviceEnumeratorLinux::SerialDeviceEnumeratorLinux(
     : tty_driver_info_path_(tty_driver_info_path) {
   DETACH_FROM_SEQUENCE(sequence_checker_);
 
-  watcher_ = UdevWatcher::StartWatching(
-      this, {UdevWatcher::Filter(kSubsystemTty, "")});
+  watcher_ = UdevWatcher::StartWatching(this);
   if (watcher_)
     watcher_->EnumerateExistingDevices();
 }
@@ -110,11 +107,9 @@ void SerialDeviceEnumeratorLinux::OnDeviceAdded(ScopedUdevDevicePtr device) {
   base::ScopedBlockingCall scoped_blocking_call(FROM_HERE,
                                                 base::BlockingType::MAY_BLOCK);
 
-#if DCHECK_IS_ON()
   const char* subsystem = udev_device_get_subsystem(device.get());
-  DCHECK(subsystem);
-  DCHECK_EQ(base::StringPiece(subsystem), kSubsystemTty);
-#endif
+  if (!subsystem || strcmp(subsystem, "tty") != 0)
+    return;
 
   const char* syspath_str = udev_device_get_syspath(device.get());
   if (!syspath_str)

services/device/usb/usb_service_linux.cc

@@ -34,8 +34,6 @@ namespace device {
 
 namespace {
 
-constexpr char kSubsystemUsb[] = "usb";
-
 // Standard USB requests and descriptor types:
 const uint16_t kUsbVersion2_1 = 0x0210;
 
@@ -111,8 +109,7 @@ void UsbServiceLinux::BlockingTaskRunnerHelper::Start() {
 
   // Initializing udev for device enumeration and monitoring may fail. In that
   // case this service will continue to exist but no devices will be found.
-  watcher_ = UdevWatcher::StartWatching(
-      this, {UdevWatcher::Filter(kSubsystemUsb, "")});
+  watcher_ = UdevWatcher::StartWatching(this);
   if (watcher_)
     watcher_->EnumerateExistingDevices();
 
@@ -126,12 +123,9 @@ void UsbServiceLinux::BlockingTaskRunnerHelper::OnDeviceAdded(
 
   base::ScopedBlockingCall scoped_blocking_call(FROM_HERE,
                                                 base::BlockingType::MAY_BLOCK);
-
-#if DCHECK_IS_ON()
   const char* subsystem = udev_device_get_subsystem(device.get());
-  DCHECK(subsystem);
-  DCHECK_EQ(base::StringPiece(subsystem), kSubsystemUsb);
-#endif
+  if (!subsystem || strcmp(subsystem, "usb") != 0)
+    return;
 
   const char* value = udev_device_get_devnode(device.get());
   if (!value)