Added trace query code and wired tracing through BrowserProxy so tests can run traces.

chrome/test/automation/browser_proxy.h

Index: chrome/test/automation/browser_proxy.h
diff --git a/chrome/test/automation/browser_proxy.h b/chrome/test/automation/browser_proxy.h
index 07f1e28cadc39aa2542f56110e20042470eed50c..a5a84d2c91abf4887643ea5ad2bfa59b6f78e1ee 100644
--- a/chrome/test/automation/browser_proxy.h
+++ b/chrome/test/automation/browser_proxy.h
@@ -232,6 +232,17 @@ class BrowserProxy : public AutomationResourceProxy {
   bool GetInitialLoadTimes(float* min_start_time, float* max_stop_time,
                            std::vector<float>* stop_times);
 
+  // Begin a trace on the browser instance.
+  // See base/event_trace.h for documentation of included/excluded categories.
+  bool BeginTracing(const std::vector<std::string>& included_categories,
+                    const std::vector<std::string>& excluded_categories);
+
+  // Helper method to begin trace on a single included category filter.
+  // Example: BeginTracing("test_MyTest*");
+  bool BeginTracing(const std::string& included_categories);
+
+  // End trace and collect the trace output as a json string.
+  bool EndTracing(std::string* json_trace_output);
 
  protected:
   virtual ~BrowserProxy() {}