memory-infra: Move dump level check to observer and rename session state

base/trace_event/memory_tracing_observer.h

Index: base/trace_event/memory_tracing_observer.h
diff --git a/base/trace_event/memory_tracing_observer.h b/base/trace_event/memory_tracing_observer.h
index 1efea18c4d552509fa5d2c59c0015f165a287a28..11276763c1a7829374c23860116fa765432ec7ef 100644
--- a/base/trace_event/memory_tracing_observer.h
+++ b/base/trace_event/memory_tracing_observer.h
@@ -33,8 +33,12 @@ class BASE_EXPORT MemoryTracingObserver
                                const ProcessMemoryDump*);
 
  private:
+  // Returns true if the dump mode is allowed for current tracing session.
+  bool IsDumpModeAllowed(MemoryDumpLevelOfDetail) const;
+
   MemoryDumpManager* const memory_dump_manager_;
   TraceLog* const trace_log_;
+  std::unique_ptr<TraceConfig::MemoryDumpConfig> memory_dump_config_;
 
   DISALLOW_COPY_AND_ASSIGN(MemoryTracingObserver);
 };