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 81b7d515133dd0c3c71f461316ced768e6fd9618..d1b11e0af3e4a73eaa214d43c29e60f94ec634e4 100644
--- a/base/trace_event/trace_config.h
+++ b/base/trace_event/trace_config.h
@@ -49,6 +49,15 @@ class BASE_EXPORT TraceConfig {
 
   typedef std::vector<MemoryDumpTriggerConfig> MemoryDumpConfig;
 
+  // Convert from DevTools style to tracing style. That is:
+  // 1. Convert dict key style: abcDefGhi => abc_def_ghi.
+  //    For example: includedCategories => included_categories
+  // 2. Convert trace record mode style: abcDefGhi => abc-def-ghi.
+  //    For example: recordUntilFull => record-until-full
+  static scoped_ptr<base::DictionaryValue> DevToolsToTracingStyle(

[caseq, 2016/03/05 02:25:24]

I think it would be better out of base -- doing this in DevTools or tracing
controller would be the best perhaps.

[Primiano Tucci (use gerrit), 2016/03/06 01:24:37]

+1. Base should not know anything about devtools.

+      const scoped_ptr<base::DictionaryValue>& devtools_style);
+  static std::string DevToolsToTracingStyle(const std::string& devtools_style);
+
   TraceConfig();
 
   // Create TraceConfig object from category filter and trace options strings.