Add profiling for FinishConfigureDataTypesOnFrontendLoop (sync).

components/sync_driver/data_type_manager_impl.cc

Index: components/sync_driver/data_type_manager_impl.cc
diff --git a/components/sync_driver/data_type_manager_impl.cc b/components/sync_driver/data_type_manager_impl.cc
index 07f79c49639e09b294a38e091b568dd3b6b93740..dfffa3c775078403ff6a0a8aa4071e9a9dbfd68a 100644
--- a/components/sync_driver/data_type_manager_impl.cc
+++ b/components/sync_driver/data_type_manager_impl.cc
@@ -13,6 +13,7 @@
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
+#include "base/profiler/scoped_tracker.h"
 #include "base/strings/stringprintf.h"
 #include "base/trace_event/trace_event.h"
 #include "components/sync_driver/data_type_controller.h"
@@ -349,12 +350,23 @@ void DataTypeManagerImpl::DownloadReady(
     syncer::ModelTypeSet high_priority_types_before,
     syncer::ModelTypeSet first_sync_types,
     syncer::ModelTypeSet failed_configuration_types) {
+  // TODO(erikchen): Remove ScopedTracker below once https://crbug.com/458406
+  // is fixed.
+  tracked_objects::ScopedTracker tracking_profile1(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "458406 DataTypeManagerImpl::DownloadReady"));
+
   DCHECK(state_ == DOWNLOAD_PENDING || state_ == CONFIGURING);
 
   // Persistence errors are reset after each backend configuration attempt
   // during which they would have been purged.
   data_type_status_table_.ResetPersistenceErrorsFrom(types_to_download);
 
+  // TODO(erikchen): Remove ScopedTracker below once https://crbug.com/458406
+  // is fixed.
+  tracked_objects::ScopedTracker tracking_profile2(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "458406 DataTypeManagerImpl::DownloadReady::NeedsReconfigure"));

[stanisc, 2015/02/17 19:25:29]

Would it make sense to define a scope for each of these nested scoped trackers.
As I understand each of them will measure time until the end of DownloadReady.

[erikchen, 2015/02/18 18:57:15]

Each ScopedTracker automatically subtracts out the time consumed by more newly
constructed ScopedTrackers.

   // Ignore |failed_configuration_types| if we need to reconfigure
   // anyway.
   if (needs_reconfigure_) {
@@ -363,6 +375,11 @@ void DataTypeManagerImpl::DownloadReady(
     return;
   }
 
+  // TODO(erikchen): Remove ScopedTracker below once https://crbug.com/458406
+  // is fixed.
+  tracked_objects::ScopedTracker tracking_profile3(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "458406 DataTypeManagerImpl::DownloadReady::UnrecoverableError"));
   if (!failed_configuration_types.Empty()) {
     if (!unrecoverable_error_method_.is_null())
       unrecoverable_error_method_.Run();
@@ -383,6 +400,11 @@ void DataTypeManagerImpl::DownloadReady(
 
   state_ = CONFIGURING;
 
+  // TODO(erikchen): Remove ScopedTracker below once https://crbug.com/458406
+  // is fixed.
+  tracked_objects::ScopedTracker tracking_profile4(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "458406 DataTypeManagerImpl::DownloadReady::Associate"));
   // Pop and associate download-ready types.
   syncer::ModelTypeSet ready_types = types_to_download;
   CHECK(!download_types_queue_.empty());
@@ -401,6 +423,11 @@ void DataTypeManagerImpl::DownloadReady(
   if (association_types_queue_.size() == 1u)
     StartNextAssociation();

[stanisc, 2015/02/17 19:25:29]

I suspect most of the time is spent here. Also take a look at
Sync.*AssociationTime histograms.

 
+  // TODO(erikchen): Remove ScopedTracker below once https://crbug.com/458406
+  // is fixed.
+  tracked_objects::ScopedTracker tracking_profile5(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "458406 DataTypeManagerImpl::DownloadReady::ConfigureDataTypes"));
   // Download types of low priority while configuring types of high priority.
   if (!new_types_to_download.Empty()) {
     configurer_->ConfigureDataTypes(