[ozone/x11] Cleaned up the code that initialises touch device list.

Ozone/X11 already initialises the touch device list in
OzonePlatformX11::InitializeUI(), where it does the same call as
StartupBrowserCreator::ProcessCmdLineImpl(), but the latter had an
UNIMPLEMENTED_LOG_ONCE macro and a TODO for supporting the feature on
Ozone.

This CL cleans the code a bit.

Bug: 1097696
Change-Id: I74c67be4d6f6ef8e1f9379463c0cb96187f1b0f4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2367058
Auto-Submit: Alexander Dunaev <adunaev@igalia.com>
Commit-Queue: Scott Violet <sky@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#800223}

chrome/browser/ui/startup/startup_browser_creator.cc

@@ -699,11 +699,10 @@ bool StartupBrowserCreator::ProcessCmdLineImpl(
 #endif  // OS_CHROMEOS
 
 #if defined(TOOLKIT_VIEWS) && defined(USE_X11)
-  // TODO(https://crbug.com/1097696): make it available on ozone/linux.
-  if (!features::IsUsingOzonePlatform())
+  if (!features::IsUsingOzonePlatform()) {
+    // Ozone sets the device list upon platform initialisation.
     ui::TouchFactory::SetTouchDeviceListFromCommandLine();
-  else
-    NOTIMPLEMENTED_LOG_ONCE();
+  }
 #endif
 
 #if defined(OS_MAC)