[ChromeDriver] Implementing PerfLoggingPrefs for perf log

chrome/test/chromedriver/capabilities.h

Index: chrome/test/chromedriver/capabilities.h
diff --git a/chrome/test/chromedriver/capabilities.h b/chrome/test/chromedriver/capabilities.h
index edef9baeac599ce7285771b811219153ffc632c6..b521e444296bf8b5bdb6998202280b41d4492f30 100644
--- a/chrome/test/chromedriver/capabilities.h
+++ b/chrome/test/chromedriver/capabilities.h
@@ -60,6 +60,27 @@ class Switches {
 
 typedef std::map<std::string, Log::Level> LoggingPrefs;
 
+struct PerfLoggingPrefs {
+  PerfLoggingPrefs();
+  ~PerfLoggingPrefs();
+
+  // We must distinguish between a log domain being set by default and being
+  // explicitly set. Otherwise, |PerformanceLogger| could only handle 3 of 4
+  // possible combinations (tracing enabled/disabled + Timeline on/off).
+  enum InspectorDomainStatus {
+    kDefaultEnabled,
+    kDefaultDisabled,
+    kExplicitlyEnabled,
+    kExplicitlyDisabled
+  };
+
+  InspectorDomainStatus network;
+  InspectorDomainStatus page;
+  InspectorDomainStatus timeline;
+
+  std::string trace_categories;  // Non-empty string enables tracing.
+};
+
 struct Capabilities {
   Capabilities();
   ~Capabilities();
@@ -114,6 +135,8 @@ struct Capabilities {
   // If set, enable minidump for chrome crashes and save to this directory.
   std::string minidump_path;
 
+  PerfLoggingPrefs perf_logging_prefs;
+
   scoped_ptr<base::DictionaryValue> prefs;
 
   Switches switches;