[subresource_filter] Add metrics for all NavigationThrottle delays

components/subresource_filter/content/browser/activation_state_computing_navigation_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/activation_state_computing_navigation_throttle.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/memory/ptr_util.h"
+#include "base/metrics/histogram_macros.h"
 #include "components/subresource_filter/content/browser/async_document_subresource_filter.h"
 #include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/web_contents.h"
 
 namespace subresource_filter {
 
 // static
 std::unique_ptr<ActivationStateComputingNavigationThrottle>
 ActivationStateComputingNavigationThrottle::CreateForMainFrame(
@@ skipping 63 matching lines @@
     content::RenderFrameHost* parent = navigation_handle()->GetParentFrame();
     DCHECK(parent);
     params.parent_document_origin = parent->GetLastCommittedOrigin();
   }
 
   async_filter_ = base::MakeUnique<AsyncDocumentSubresourceFilter>(
       ruleset_handle_, std::move(params),
       base::Bind(&ActivationStateComputingNavigationThrottle::
                      OnActivationStateComputed,
                  weak_ptr_factory_.GetWeakPtr()));
+
+  defer_timestamp_ = base::TimeTicks::Now();
   return content::NavigationThrottle::ThrottleCheckResult::DEFER;
 }
 
 const char* ActivationStateComputingNavigationThrottle::GetNameForLogging() {
   return "ActivationStateComputingNavigationThrottle";
 }
 
 void ActivationStateComputingNavigationThrottle::OnActivationStateComputed(
     ActivationState state) {
+  DCHECK(!defer_timestamp_.is_null());
+  base::TimeDelta delay = base::TimeTicks::Now() - defer_timestamp_;
+  UMA_HISTOGRAM_TIMES("SubresourceFilter.DocumentLoad.ActivationComputingDelay",

[pkalinnikov, 2017/05/08 12:00:05]

Do you expect it to be mostly >= 1 ms?

We also have microseconds-precision macros in
c/s_f/core/common/time_measurements.h (see UMA_HISTOGRAM_MICRO_TIMES).

[Charlie Harrison, 2017/05/08 12:53:33]

Yeah we can us microseconds for these metrics (maybe for the filtering ones as
well). I think I would feel more comfortable in the latter case using a
histogram with a ceiling > 1 second though using custom times.

+                      delay);
+  if (navigation_handle()->IsInMainFrame()) {
+    UMA_HISTOGRAM_TIMES(
+        "SubresourceFilter.DocumentLoad.ActivationComputingDelay.MainFrame",
+        delay);
+  }
   navigation_handle()->Resume();
 }
 
 // Ensure the caller cannot take ownership of a subresource filter for cases
 // when activation IPCs are not sent to the render process.
 std::unique_ptr<AsyncDocumentSubresourceFilter>
 ActivationStateComputingNavigationThrottle::ReleaseFilter() {
   return will_send_activation_to_renderer_ ? std::move(async_filter_) : nullptr;
 }
 
 void ActivationStateComputingNavigationThrottle::
     WillSendActivationToRenderer() {
   DCHECK(async_filter_);
   will_send_activation_to_renderer_ = true;
 }
 
 }  // namespace subresource_filter