Remove line number from rtc::Location

Concatenating __FILE__ with __LINE__ prevents the compiler from
aliasing strings within the same file, contributing ~30KB of .text
bloat. Chrome already omits from the file number from its Location
type so it doesn't seem to be a big loss.

Bug: b/145168048
Change-Id: I000bfdf43f4eb90f8b63ed017b08c1b5a7a84a6d
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/160744
Commit-Queue: Steve Anton <steveanton@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29994}

modules/utility/source/process_thread_impl.cc

@@ -190,7 +190,7 @@ bool ProcessThreadImpl::Process() {
         {
           TRACE_EVENT2("webrtc", "ModuleProcess", "function",
                        m.location.function_name(), "file",
-                       m.location.file_and_line());
+                       m.location.file_name());
           m.module->Process();
         }
         // Use a new 'now' reference to calculate when the next callback