Revert of Update DevTools Tracing.Start to accept trace config as a parameter

base/trace_event/trace_config.h

Index: base/trace_event/trace_config.h
diff --git a/base/trace_event/trace_config.h b/base/trace_event/trace_config.h
index 75e001b275974ef0cfae4230485d029cd68a82f2..81b7d515133dd0c3c71f461316ced768e6fd9618 100644
--- a/base/trace_event/trace_config.h
+++ b/base/trace_event/trace_config.h
@@ -130,10 +130,6 @@
   // disabled-by-default-memory-infra category is enabled.
   explicit TraceConfig(const std::string& config_string);
 
-  // Functionally identical to the above, but takes a parsed dictionary as input
-  // instead of its JSON serialization.
-  explicit TraceConfig(const DictionaryValue& config);
-
   TraceConfig(const TraceConfig& tc);
 
   ~TraceConfig();
@@ -194,10 +190,7 @@
   // in the suffix 'Debug' or 'Test'.
   void InitializeDefault();
 
-  // Initialize from a config dictionary.
-  void InitializeFromConfigDict(const DictionaryValue& dict);
-
-  // Initialize from a config string.
+  // Initialize from the config string
   void InitializeFromConfigString(const std::string& config_string);
 
   // Initialize from category filter and trace options strings