Add Tracing.getCategories to devtools_tracing_handler.cc.

content/browser/devtools/devtools_tracing_handler.cc

Index: content/browser/devtools/devtools_tracing_handler.cc
diff --git a/content/browser/devtools/devtools_tracing_handler.cc b/content/browser/devtools/devtools_tracing_handler.cc
index 19ec9769d48f65c9b2ad34e463298866743dd4e5..7d308642212bf5c74d572babc1c029f180834af7 100644
--- a/content/browser/devtools/devtools_tracing_handler.cc
+++ b/content/browser/devtools/devtools_tracing_handler.cc
@@ -55,6 +55,9 @@ DevToolsTracingHandler::DevToolsTracingHandler(
   RegisterCommandHandler(devtools::Tracing::end::kName,
                          base::Bind(&DevToolsTracingHandler::OnEnd,
                                     base::Unretained(this)));
+  RegisterCommandHandler(devtools::Tracing::getCategories::kName,
+                         base::Bind(&DevToolsTracingHandler::OnGetCategories,
+                                    base::Unretained(this)));
 }
 
 DevToolsTracingHandler::~DevToolsTracingHandler() {
@@ -217,4 +220,29 @@ void DevToolsTracingHandler::OnClientDetached() {
     DisableRecording();
 }
 
+scoped_refptr<DevToolsProtocol::Response>
+DevToolsTracingHandler::OnGetCategories(
+    scoped_refptr<DevToolsProtocol::Command> command) {
+  TracingController::GetInstance()->GetCategories(
+      base::Bind(&DevToolsTracingHandler::OnCategoriesReceived,
+                 weak_factory_.GetWeakPtr(),
+                 command));
+  return command->AsyncResponsePromise();
+}
+
+void DevToolsTracingHandler::OnCategoriesReceived(
+    scoped_refptr<DevToolsProtocol::Command> command,
+    const std::set<std::string>& category_set) {
+  base::DictionaryValue* response = new base::DictionaryValue;
+  base::ListValue* category_list = new base::ListValue;
+  for (std::set<std::string>::const_iterator it = category_set.begin();
+       it != category_set.end(); ++it) {
+    category_list->AppendString(*it);
+  }
+
+  response->Set(devtools::Tracing::getCategories::kResponseCategories,
+                category_list);
+  SendAsyncResponse(command->SuccessResponse(response));
+}
+
 }  // namespace content