Background Tracing: Remove safety check for crash exit on Android

chrome/browser/tracing/chrome_tracing_delegate.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/tracing/chrome_tracing_delegate.h"
 
 #include <utility>
 
 #include "base/time/time.h"
 #include "build/build_config.h"
@@ skipping 65 matching lines @@
 
   // If the profile hasn't loaded or been created yet, we allow the scenario
   // to start up, but not be finalized.
   if (!profile) {
     if (profile_permission == PROFILE_REQUIRED)
       return false;
     else
       return true;
   }
 
+#if !defined(OS_ANDROID)
   // Safeguard, in case background tracing is responsible for a crash on
   // startup.
   if (profile->GetLastSessionExitType() == Profile::EXIT_CRASHED)
     return false;
+#else
+  // In case of Android the exit state is always set as EXIT_CRASHED. So,
+  // preemptive mode cannot be used safely.
+  if (config.tracing_mode() == content::BackgroundTracingConfig::PREEMPTIVE)
+    return false;
+#endif
 
   PrefService* local_state = g_browser_process->local_state();
   DCHECK(local_state);
 
 #if !defined(OS_CHROMEOS) && defined(OFFICIAL_BUILD)
   if (!local_state->GetBoolean(metrics::prefs::kMetricsReportingEnabled))
     return false;
 #endif // !OS_CHROMEOS && OFFICIAL_BUILD
 
   if (config.tracing_mode() == content::BackgroundTracingConfig::PREEMPTIVE) {
@@ skipping 66 matching lines @@
   for (const auto& it : variations)
     variations_list->AppendString(it);
 
   metadata_dict->Set("field-trials", std::move(variations_list));
 }
 
 content::MetadataFilterPredicate
 ChromeTracingDelegate::GetMetadataFilterPredicate() {
   return base::Bind(&IsMetadataWhitelisted);
 }