[subresource_filter] Add metrics for all NavigationThrottle delays

components/subresource_filter/content/browser/subframe_navigation_filtering_throttle.cc

 // Copyright 2017 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/subframe_navigation_filtering_throttle.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
+#include "base/metrics/histogram_macros.h"
 #include "content/public/browser/navigation_handle.h"
 
 namespace subresource_filter {
 
 SubframeNavigationFilteringThrottle::SubframeNavigationFilteringThrottle(
     content::NavigationHandle* handle,
     AsyncDocumentSubresourceFilter* parent_frame_filter)
     : content::NavigationThrottle(handle),
       parent_frame_filter_(parent_frame_filter),
       weak_ptr_factory_(this) {
   DCHECK(!handle->IsInMainFrame());
   DCHECK(parent_frame_filter_);
 }
 
-SubframeNavigationFilteringThrottle::~SubframeNavigationFilteringThrottle() {}
+SubframeNavigationFilteringThrottle::~SubframeNavigationFilteringThrottle() {
+  if (disallowed_) {
+    UMA_HISTOGRAM_TIMES(
+        "SubresourceFilter.DocumentLoad.SubframeFilteringDelay.Disallowed",
+        total_defer_time_);
+  } else {
+    UMA_HISTOGRAM_TIMES(
+        "SubresourceFilter.DocumentLoad.SubframeFilteringDelay.Allowed",
+        total_defer_time_);
+  }
+}
 
 content::NavigationThrottle::ThrottleCheckResult
 SubframeNavigationFilteringThrottle::WillStartRequest() {
   return DeferToCalculateLoadPolicy();
 }
 
 content::NavigationThrottle::ThrottleCheckResult
 SubframeNavigationFilteringThrottle::WillRedirectRequest() {
   return DeferToCalculateLoadPolicy();
 }
 
 const char* SubframeNavigationFilteringThrottle::GetNameForLogging() {
   return "SubframeNavigationFilteringThrottle";
 }
 
 content::NavigationThrottle::ThrottleCheckResult
 SubframeNavigationFilteringThrottle::DeferToCalculateLoadPolicy() {
   parent_frame_filter_->GetLoadPolicyForSubdocument(
       navigation_handle()->GetURL(),
       base::Bind(&SubframeNavigationFilteringThrottle::OnCalculatedLoadPolicy,
                  weak_ptr_factory_.GetWeakPtr()));
+  last_defer_time_ = base::TimeTicks::Now();
   return content::NavigationThrottle::ThrottleCheckResult::DEFER;
 }
 
 void SubframeNavigationFilteringThrottle::OnCalculatedLoadPolicy(
     LoadPolicy policy) {
+  DCHECK(!last_defer_time_.is_null());
+  total_defer_time_ += base::TimeTicks::Now() - last_defer_time_;
   // TODO(csharrison): Support WouldDisallow pattern and expose the policy for
   // metrics. Also, cancel with BLOCK_AND_COLLAPSE when it is implemented.
   if (policy == LoadPolicy::DISALLOW) {
+    disallowed_ = true;
     parent_frame_filter_->ReportDisallowedLoad();
     navigation_handle()->CancelDeferredNavigation(
         content::NavigationThrottle::CANCEL);
   } else {
     navigation_handle()->Resume();
   }
 }
 
 }  // namespace subresource_filter