tracing/keyed_services: Use typed trace event for service lookup

Replaces the KeyedServiceFactory::GetServiceForContext trace event with
a typed trace event.

Corresponding proto buffer definitions for these events were added in
aosp/1180211.

Typed trace events will allow inclusion of the event arguments in slow
reports data in the future. The trace format is protocol-buffer based
under the hood already (see docs.perfetto.dev for details), this patch
adds strong typing for the arguments of the respective event(s) only.

TBR: eseckler@google.com
Bug: 644264
Change-Id: I67c0f8f78caca2db76e201f8f649f84eda53e3fc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1950966
Commit-Queue: Eric Seckler <eseckler@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#735359}

components/keyed_service/core/BUILD.gn

@@ -42,6 +42,7 @@ component("core") {
     "//base",
     "//components/pref_registry",
     "//components/prefs",
+    "//services/tracing/public/cpp:cpp",
   ]
 }
 

components/keyed_service/core/DEPS

 include_rules = [
+  "+services/tracing/public/cpp",
+  "+third_party/perfetto/protos/perfetto/trace/track_event",
   # Only for tests.
   "+third_party/re2",
 ]

components/keyed_service/core/keyed_service_base_factory.cc

@@ -4,6 +4,8 @@
 
 #include "components/keyed_service/core/keyed_service_base_factory.h"
 
+#include <type_traits>
+
 #include "base/supports_user_data.h"
 #include "base/trace_event/trace_event.h"
 #include "components/keyed_service/core/dependency_manager.h"
@@ -14,6 +16,15 @@ KeyedServiceBaseFactory::KeyedServiceBaseFactory(const char* service_name,
                                                  DependencyManager* manager,
                                                  Type type)
     : dependency_manager_(manager), service_name_(service_name), type_(type) {
+  static_assert(
+      std::is_same<decltype(KeyedServiceBaseFactory::service_name_),
+                   const char*>::value,
+      "This string is logged in plaintext via UMA trace events uploads, so "
+      "must be static as a privacy requirement. See //third_party/perfetto/"
+      "protos/perfetto/trace/track_event/chrome_keyed_service.proto. "
+      "Contact tracing@chromium.org and base/metrics/OWNERS if this needs to "
+      "change.");
+
   dependency_manager_->AddComponent(this);
 }
 

components/keyed_service/core/keyed_service_factory.cc

@@ -8,9 +8,10 @@
 
 #include "base/logging.h"
 #include "base/stl_util.h"
-#include "base/trace_event/trace_event.h"
 #include "components/keyed_service/core/dependency_manager.h"
 #include "components/keyed_service/core/keyed_service.h"
+#include "services/tracing/public/cpp/perfetto/macros.h"
+#include "third_party/perfetto/protos/perfetto/trace/track_event/chrome_keyed_service.pbzero.h"
 
 KeyedServiceFactory::KeyedServiceFactory(const char* name,
                                          DependencyManager* manager,
@@ -48,8 +49,10 @@ KeyedService* KeyedServiceFactory::SetTestingFactoryAndUse(
 
 KeyedService* KeyedServiceFactory::GetServiceForContext(void* context,
                                                         bool create) {
-  TRACE_EVENT1("browser,startup", "KeyedServiceFactory::GetServiceForContext",
-               "service_name", name());
+  TRACE_EVENT("browser,startup", "KeyedServiceFactory::GetServiceForContext",
+              [this](perfetto::EventContext ctx) {
+                ctx.event()->set_chrome_keyed_service()->set_name(name());
+              });
   context = GetContextToUse(context);
   if (!context)
     return nullptr;