[subresource_filter] Add TRACE_EVENT probes for frame activation

components/subresource_filter/content/browser/content_subresource_filter_throttle_manager.cc

Index: components/subresource_filter/content/browser/content_subresource_filter_throttle_manager.cc
diff --git a/components/subresource_filter/content/browser/content_subresource_filter_throttle_manager.cc b/components/subresource_filter/content/browser/content_subresource_filter_throttle_manager.cc
index 6b57efe16887a80688b7642f60bcaca6b9c30edf..48118c631afa3c4d704de54ff66b363159145944 100644
--- a/components/subresource_filter/content/browser/content_subresource_filter_throttle_manager.cc
+++ b/components/subresource_filter/content/browser/content_subresource_filter_throttle_manager.cc
@@ -4,9 +4,13 @@
 
 #include "components/subresource_filter/content/browser/content_subresource_filter_throttle_manager.h"
 
+#include <utility>
+
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
+#include "base/trace_event/trace_event.h"
+#include "base/trace_event/trace_event_argument.h"
 #include "components/subresource_filter/content/browser/activation_state_computing_navigation_throttle.h"
 #include "components/subresource_filter/content/browser/async_document_subresource_filter.h"
 #include "components/subresource_filter/content/browser/page_load_statistics.h"
@@ -68,6 +72,11 @@ void ContentSubresourceFilterThrottleManager::ReadyToCommitNavigation(
     return;
   }
 
+  TRACE_EVENT1(
+      TRACE_DISABLED_BY_DEFAULT("loading"),
+      "ContentSubresourceFilterThrottleManager::ReadyToCommitNavigation",
+      "activation_state", filter->activation_state().ToTracedValue());
+
   throttle->second->WillSendActivationToRenderer();
 
   content::RenderFrameHost* frame_host =