Made the NavigationTracingObserver always be active whenever background tracing is active

content/browser/tracing/background_tracing_manager_impl.h

 // 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.
 
 #ifndef CONTENT_BROWSER_TRACING_BACKGROUND_TRACING_MANAGER_IMPL_H_
 #define CONTENT_BROWSER_TRACING_BACKGROUND_TRACING_MANAGER_IMPL_H_
 
 #include "base/lazy_instance.h"
 #include "base/memory/ref_counted_memory.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 19 matching lines @@
   void WhenIdle(IdleCallback idle_callback) override;
 
   void TriggerNamedEvent(TriggerHandle, StartedFinalizingCallback) override;
   TriggerHandle RegisterTriggerType(const char* trigger_name) override;
 
   void OnHistogramTrigger(const std::string& histogram_name);
 
   void OnRuleTriggered(const BackgroundTracingRule* triggered_rule,
                        StartedFinalizingCallback callback);
   void AbortScenario();
+  bool HasActiveScenario() override;
 
   // For tests
   void InvalidateTriggerHandlesForTesting() override;
   void SetTracingEnabledCallbackForTesting(
       const base::Closure& callback) override;
   CONTENT_EXPORT void SetRuleTriggeredCallbackForTesting(
       const base::Closure& callback);
   void FireTimerForTesting() override;
-  bool HasActiveScenarioForTesting() override;
   CONTENT_EXPORT bool IsTracingForTesting();
 
  private:
   BackgroundTracingManagerImpl();
   ~BackgroundTracingManagerImpl() override;
 
   void EnableRecording(std::string, base::trace_event::TraceRecordMode);
   void EnableRecordingIfConfigNeedsIt();
   void OnFinalizeStarted(base::RefCountedString*);
   void OnFinalizeComplete();
@@ skipping 46 matching lines @@
   base::Closure rule_triggered_callback_for_testing_;
 
   friend struct base::DefaultLazyInstanceTraits<BackgroundTracingManagerImpl>;
 
   DISALLOW_COPY_AND_ASSIGN(BackgroundTracingManagerImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_TRACING_BACKGROUND_TRACING_MANAGER_IMPL_H_