[subresource_filter] Add debugging trace events around activation

components/subresource_filter/content/browser/content_subresource_filter_driver_factory.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/subresource_filter/content/browser/content_subresource_filter_driver_factory.h"
 
 #include "base/feature_list.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/rand_util.h"
 #include "base/time/time.h"
+#include "base/trace_event/trace_event.h"
+#include "base/trace_event/trace_event_argument.h"
 #include "components/subresource_filter/content/browser/content_activation_list_utils.h"
 #include "components/subresource_filter/content/browser/subresource_filter_client.h"
 #include "components/subresource_filter/core/browser/subresource_filter_features.h"
 #include "components/subresource_filter/core/common/activation_list.h"
 #include "components/subresource_filter/core/common/activation_state.h"
 #include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/navigation_throttle.h"
 #include "content/public/browser/web_contents.h"
 #include "net/base/net_errors.h"
 #include "url/gurl.h"
@@ skipping 90 matching lines @@
 
   const auto config_list = GetEnabledConfigurations();
   const auto highest_priority_activated_config =
       std::find_if(config_list->configs_by_decreasing_priority().begin(),
                    config_list->configs_by_decreasing_priority().end(),
                    [&url, this](const Configuration& config) {
                      return DoesMainFrameURLSatisfyActivationConditions(
                          url, config.activation_conditions);
                    });
 
-  if (highest_priority_activated_config ==
-      config_list->configs_by_decreasing_priority().end()) {
+  bool matched_config = highest_priority_activated_config !=

[engedy, 2017/05/15 12:10:38]

nit: s//has_activated_config/ for consistency with above.

[Charlie Harrison, 2017/05/15 15:14:22]

Done.

+                        config_list->configs_by_decreasing_priority().end();
+  TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("loading"),

[engedy, 2017/05/15 12:10:37]

nit: The TRACE_EVENT in document_subresource_filter.cc:67 uses the category
"loader". This is intended, right?

[Charlie Harrison, 2017/05/15 15:14:22]

I think "loading" is the category we should be using, and "loader" is
deprecated, though I don't think it is a very big deal. I can look into changing
that one in a followup after clarification with loading team.

+               "ContentSubresourceFilterDriverFactory::"
+               "ComputeActivationForMainFrameNavigation",
+               "highest_priority_activated_config",
+               matched_config
+                   ? highest_priority_activated_config->GetTracedValue()
+                   : base::MakeUnique<base::trace_event::TracedValue>());
+  if (!matched_config) {
     activation_decision_ = ActivationDecision::ACTIVATION_CONDITIONS_NOT_MET;
     activation_options_ = Configuration::ActivationOptions();
     return;
   }
 
   activation_options_ = highest_priority_activated_config->activation_options;
   activation_decision_ =
       activation_options_.activation_level == ActivationLevel::DISABLED
           ? ActivationDecision::ACTIVATION_DISABLED
           : ActivationDecision::ACTIVATED;
@@ skipping 64 matching lines @@
   DCHECK_NE(activation_decision_, ActivationDecision::UNKNOWN);
 
   // Check for whitelisted status last, so that the client gets an accurate
   // indication of whether there would be activation otherwise.
   bool whitelisted = client_->OnPageActivationComputed(
       navigation_handle,
       activation_options_.activation_level == ActivationLevel::ENABLED);
 
   // Only reset the activation decision reason if we would have activated.
   if (whitelisted && activation_decision_ == ActivationDecision::ACTIVATED) {
+    TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("loading"), "ActivationWhitelisted");
     activation_decision_ = ActivationDecision::URL_WHITELISTED;
     activation_options_ = Configuration::ActivationOptions();
   }
 
   if (activation_decision_ != ActivationDecision::ACTIVATED) {
     DCHECK_EQ(activation_options_.activation_level, ActivationLevel::DISABLED);
     return;
   }
 
   DCHECK_NE(activation_options_.activation_level, ActivationLevel::DISABLED);
@@ skipping 117 matching lines @@
       REPORT_REDIRECT_PATTERN_FOR_SUFFIX("SubresourceFilterOnly", hits_pattern,
                                          chain_size);
       break;
     default:
       NOTREACHED();
       break;
   }
 }
 
 }  // namespace subresource_filter