cros: Rename touch_log_source_ozone.cc to touch_log_source.cc

All Chrome OS platforms use ozone. Make the filename match the
header.

Bug: none
Test: compiles
Change-Id: I0b62471c2eab082fe9863aa1db8976fbddc24d2d
Reviewed-on: https://chromium-review.googlesource.com/894737Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Commit-Queue: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533274}

chrome/browser/chromeos/BUILD.gn

@@ -1550,8 +1550,8 @@ source_set("chromeos") {
     "system_logs/single_debug_daemon_log_source.h",
     "system_logs/single_log_file_log_source.cc",
     "system_logs/single_log_file_log_source.h",
+    "system_logs/touch_log_source.cc",
     "system_logs/touch_log_source.h",
-    "system_logs/touch_log_source_ozone.cc",
     "tether/fake_tether_service.cc",
     "tether/fake_tether_service.h",
     "tether/tether_service.cc",