arc: enable Android tracing in verified-boot mode

components/arc/common/tracing.mojom

Index: components/arc/common/tracing.mojom
diff --git a/components/arc/common/tracing.mojom b/components/arc/common/tracing.mojom
index e27d89ba0b3ec3afa18dd26f1874e57c9341da68..8d054ce6efb97428c69420fafe590545970cd17f 100644
--- a/components/arc/common/tracing.mojom
+++ b/components/arc/common/tracing.mojom
@@ -10,8 +10,10 @@ interface TracingInstance {
   // Queries available tracing categories in the container.
   QueryAvailableCategories@0() => (array<string> categories);
 
-  // Starts tracing in the container with the given categories.
-  StartTracing@1(array<string> categories) => (bool success);
+  // Starts tracing in the container with the given categories. A handle is
+  // passed to the client for sending trace events back to the host. The client
+  // should send trace event as a JSON object in each write.
+  StartTracing@1(array<string> categories, handle sock) => (bool success);
 
   // Stops tracing in the container.
   StopTracing@2() => (bool success);