decode strings to utf-8 and use universal_newlines for subprocess

Bug: webrtc:13607
Change-Id: I4d8df7488b819b477cd0ae5553c0eb8a7adfb179
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/251343
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Christoffer Jansson <jansson@google.com>
Cr-Commit-Position: refs/heads/main@{#35955}

tools_webrtc/perf/catapult_uploader.py

@@ -24,7 +24,10 @@ from tracing.value.diagnostics import reserved_infos
 
 def _GenerateOauthToken():
   args = ['luci-auth', 'token']
-  p = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+  p = subprocess.Popen(args,
+                       universal_newlines=True,
+                       stdout=subprocess.PIPE,
+                       stderr=subprocess.PIPE)
   if p.wait() == 0:
     output = p.stdout.read()
     return output.strip()
@@ -193,7 +196,7 @@ def _ApplyHacks(dicts):
 def _LoadHistogramSetFromProto(options):
   hs = histogram_set.HistogramSet()
   with options.input_results_file as f:
-    hs.ImportProto(f.read())
+    hs.ImportProto(f.read().decode('utf-8'))
 
   return hs