PlzNavigate: Add metrics to understand bf navigations PLT regression

content/browser/frame_host/navigation_handle_impl.cc

 // Copyright 2015 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 "content/browser/frame_host/navigation_handle_impl.h"
 
 #include <iterator>
 
 #include "base/logging.h"
+#include "base/metrics/histogram_macros.h"
 #include "content/browser/appcache/appcache_navigation_handle.h"
 #include "content/browser/appcache/appcache_service_impl.h"
 #include "content/browser/child_process_security_policy_impl.h"
 #include "content/browser/devtools/render_frame_devtools_agent_host.h"
 #include "content/browser/frame_host/ancestor_throttle.h"
 #include "content/browser/frame_host/data_url_navigation_throttle.h"
 #include "content/browser/frame_host/debug_urls.h"
 #include "content/browser/frame_host/form_submission_throttle.h"
 #include "content/browser/frame_host/frame_tree_node.h"
 #include "content/browser/frame_host/mixed_content_navigation_throttle.h"
@@ skipping 679 matching lines @@
 }
 
 void NavigationHandleImpl::ReadyToCommitNavigation(
     RenderFrameHostImpl* render_frame_host) {
   TRACE_EVENT_ASYNC_STEP_INTO0("navigation", "NavigationHandle", this,
                                "ReadyToCommitNavigation");
 
   DCHECK(!render_frame_host_ || render_frame_host_ == render_frame_host);
   render_frame_host_ = render_frame_host;
   state_ = READY_TO_COMMIT;
+  ready_to_commit_time_ = base::TimeTicks::Now();
+
+  // For back-forward navigations, record metrics.
+  if (transition_ & ui::PAGE_TRANSITION_FORWARD_BACK) {
+    bool is_same_process =
+        render_frame_host_->GetProcess()->GetID() ==
+        frame_tree_node_->current_frame_host()->GetProcess()->GetID();
+    UMA_HISTOGRAM_BOOLEAN("Navigation.BackForward.IsSameProcess",
+                          is_same_process);
+    UMA_HISTOGRAM_TIMES("Navigation.BackForward.TimeToReadyToCommit",
+                        ready_to_commit_time_ - navigation_start_);
+  }
 
   if (IsBrowserSideNavigationEnabled())
     SetExpectedProcess(render_frame_host->GetProcess());
 
   if (!IsRendererDebugURL(url_) && !IsSameDocument())
     GetDelegate()->ReadyToCommitNavigation(this);
 }
 
 void NavigationHandleImpl::DidCommitNavigation(
     const FrameHostMsg_DidCommitProvisionalLoad_Params& params,
@@ skipping 10 matching lines @@
   method_ = params.method;
   has_user_gesture_ = (params.gesture == NavigationGestureUser);
   transition_ = params.transition;
   should_update_history_ = params.should_update_history;
   render_frame_host_ = render_frame_host;
   previous_url_ = previous_url;
   base_url_ = params.base_url;
   socket_address_ = params.socket_address;
   navigation_type_ = navigation_type;
 
+  // For back-forward navigations, record metrics.
+  if ((transition_ & ui::PAGE_TRANSITION_FORWARD_BACK) &&
+      !ready_to_commit_time_.is_null()) {
+    UMA_HISTOGRAM_TIMES("Navigation.BackForward.ReadyToCommitUntilCommit",
+                        base::TimeTicks::Now() - ready_to_commit_time_);
+  }
+
   DCHECK(!IsInMainFrame() || navigation_entry_committed)
       << "Only subframe navigations can get here without changing the "
       << "NavigationEntry";
   subframe_entry_committed_ = navigation_entry_committed;
 
   // If an error page reloads, net_error_code might be 200 but we still want to
   // count it as an error page.
   if (params.base_url.spec() == kUnreachableWebDataURL ||
       net_error_code_ != net::OK) {
     TRACE_EVENT_ASYNC_STEP_INTO0("navigation", "NavigationHandle", this,
@@ skipping 384 matching lines @@
   if (new_site_url == site_url_)
     return;
 
   // When redirecting cross-site, stop telling the speculative
   // RenderProcessHost to expect a navigation commit.
   SetExpectedProcess(nullptr);
   site_url_ = new_site_url;
 }
 
 }  // namespace content