[subresource_filter] Remove some state from the driver factory

chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer.cc

Index: chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer.cc
diff --git a/chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer.cc b/chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer.cc
index 28945757727e74fc45360b6c351d0194484b0a16..e290af52293d2156ca7002a0dd2bc0e904c3e50d 100644
--- a/chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer.cc
+++ b/chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer.cc
@@ -6,12 +6,13 @@
 
 #include "chrome/browser/page_load_metrics/page_load_metrics_util.h"
 #include "components/subresource_filter/content/browser/content_subresource_filter_driver_factory.h"
+#include "components/subresource_filter/content/browser/content_subresource_filter_throttle_manager.h"
+#include "components/subresource_filter/core/common/activation_decision.h"
 #include "third_party/WebKit/public/platform/WebLoadingBehaviorFlag.h"
 
 using subresource_filter::ContentSubresourceFilterDriverFactory;
 
-using ActivationDecision = subresource_filter::
-    ContentSubresourceFilterDriverFactory::ActivationDecision;
+using ActivationDecision = subresource_filter::ActivationDecision;
 
 namespace internal {
 
@@ -157,7 +158,8 @@ SubresourceFilterMetricsObserver::OnCommit(
   if (subres_filter)
     LogActivationDecisionMetrics(
         navigation_handle,
-        subres_filter->GetActivationDecisionForLastCommittedPageLoad());
+        subres_filter->throttle_manager()

[engedy, 2017/04/27 13:59:52]

I can see two somewhat acceptable options here (read my overall comments first):

 -- Keep the semantics of this method as is, but add enough delay here to make
sure we are not calling methods named `...ForLastCommittedPageLoad` until after
the page load really has been committed. :-)

 -- Store the |activation_decison| on the SafeBrowsingActivationThrottle so that
it can be accessed anytime after ReadyToCommit. Retrieve the throttle here from
the ContentSubresourceFilterDriverFactory replacement in exchange for giving it
the |navigation_handle|.

I think the second would be the nicer solution.

+            ->GetActivationDecisionForLastCommittedPageLoad());
   return CONTINUE_OBSERVING;
 }