policy_fuzzer: Reduce log spam

Disable the non-fatal logging, because fuzzing triggers tons of such
messages, which are useless and only slow down the fuzzing.

Note that some of the logging spam - mainly caused by the SYSLOG macros
- stays intact, since there's no easy way to disable those.

Bug: 811690
Change-Id: I9f93b0e2450d8ff9ec7c7a9a8c88c3c23947e7ba
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2215827Reviewed-by: Olya Kalitova <okalitova@chromium.org>
Commit-Queue: Maksim Ivanov <emaxx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#772179}

chrome/browser/chromeos/policy/fuzzer/policy_fuzzer.cc

@@ -4,6 +4,7 @@
 
 #include "base/check_op.h"
 #include "base/command_line.h"
+#include "base/logging.h"
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/chromeos/policy/device_policy_decoder_chromeos.h"
 #include "chrome/browser/chromeos/policy/fuzzer/policy_fuzzer.pb.h"
@@ -18,6 +19,7 @@
 namespace policy {
 
 bool FuzzTestInitializer() {
+  logging::SetMinLogLevel(logging::LOG_FATAL);
   base::CommandLine::Init(0, nullptr);
   chromeos::DBusThreadManager::Initialize();
   return true;