Add a second format to the tracing json/begin_recording endpoint.

content/browser/tracing/tracing_ui.h

Index: content/browser/tracing/tracing_ui.h
diff --git a/content/browser/tracing/tracing_ui.h b/content/browser/tracing/tracing_ui.h
index fdbe0c197f9a7807c6a104e1def09694d7f69cc6..ce7718f4c82b833d28852e84057221578357f4b9 100644
--- a/content/browser/tracing/tracing_ui.h
+++ b/content/browser/tracing/tracing_ui.h
@@ -15,6 +15,12 @@
 #include "content/public/browser/trace_uploader.h"
 #include "content/public/browser/web_ui_controller.h"
 
+namespace base {
+namespace trace_event {
+class TraceConfig;
+}  // namespace trace_event
+}  // namespace base
+
 namespace content {
 
 class TracingDelegate;
@@ -27,6 +33,10 @@ class CONTENT_EXPORT TracingUI : public WebUIController {
   void OnTraceUploadProgress(int64_t current, int64_t total);
   void OnTraceUploadComplete(bool success, const std::string& feedback);
 
+  // Public for testing.
+  static bool GetTracingOptions(const std::string& data64,

[Primiano Tucci (use gerrit), 2017/06/22 19:04:47]

static functions should go on the top. But also if this is the only change here,
not worth the hassle of another patchset.

[erikchen, 2017/06/22 19:30:45]

Done.

+                                base::trace_event::TraceConfig* trace_config);
+
  private:
   void DoUploadInternal(const std::string& file_contents,
                         TraceUploader::UploadMode upload_mode);