[tracing] Introduce "allowed_dump_modes" for memory dump config

base/trace_event/memory_dump_manager.h

Index: base/trace_event/memory_dump_manager.h
diff --git a/base/trace_event/memory_dump_manager.h b/base/trace_event/memory_dump_manager.h
index 4b83f685a7236af627f9f842e23d7a14e36f349c..06b772c6e4bd5f050ee6079ba6aacf1b987dfb19 100644
--- a/base/trace_event/memory_dump_manager.h
+++ b/base/trace_event/memory_dump_manager.h
@@ -116,10 +116,14 @@ class BASE_EXPORT MemoryDumpManager : public TraceLog::EnabledStateObserver {
   void OnTraceLogEnabled() override;
   void OnTraceLogDisabled() override;
 
+  // Returns true if the dump mode is allowed for current tracing session.
+  bool IsDumpModeAllowed(MemoryDumpLevelOfDetail dump_mode);
+
   // Returns the MemoryDumpSessionState object, which is shared by all the
   // ProcessMemoryDump and MemoryAllocatorDump instances through all the tracing
   // session lifetime.
-  const scoped_refptr<MemoryDumpSessionState>& session_state() const {
+  const scoped_refptr<MemoryDumpSessionState>& session_state_for_testing()
+      const {
     return session_state_;
   }