[page_load_metrics] Log cache warmth ratios at parse stop

chrome/browser/page_load_metrics/metrics_web_contents_observer.cc

Index: chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
diff --git a/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc b/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
index f34a99596684586f6fd870b85392677e2762b6e4..1c004f9a08c580d8c3f9c6b3e288c747973a9321 100644
--- a/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
+++ b/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
@@ -259,6 +259,10 @@ PageLoadTracker::PageLoadTracker(
       abort_type_(ABORT_NONE),
       started_in_foreground_(in_foreground),
       page_transition_(navigation_handle->GetPageTransition()),
+      cache_subresource_bytes_(0),
+      network_subresource_bytes_(0),
+      cache_requests_(0),
+      network_requests_(0),
       aborted_chain_size_(aborted_chain_size),
       aborted_chain_size_same_url_(aborted_chain_size_same_url),
       embedder_interface_(embedder_interface) {
@@ -478,6 +482,16 @@ bool PageLoadTracker::UpdateTiming(const PageLoadTiming& new_timing,
   return false;
 }
 
+void PageLoadTracker::OnLoadedSubresource(int64_t bytes, bool was_cached) {
+  if (was_cached) {
+    ++cache_requests_;
+    cache_subresource_bytes_ += bytes;
+  } else {
+    ++network_requests_;
+    network_subresource_bytes_ += bytes;
+  }
+}
+
 void PageLoadTracker::StopTracking() {
   did_stop_tracking_ = true;
 }
@@ -545,7 +559,8 @@ PageLoadExtraInfo PageLoadTracker::ComputePageLoadExtraInfo() {
   return PageLoadExtraInfo(
       first_background_time, first_foreground_time, started_in_foreground_,
       commit_time_.is_null() ? GURL() : url_, time_to_commit, abort_type_,
-      time_to_abort, metadata_);
+      time_to_abort, cache_subresource_bytes_, network_subresource_bytes_,
+      cache_requests_, network_requests_, metadata_);
 }
 
 void PageLoadTracker::NotifyAbort(UserAbortType abort_type,
@@ -732,6 +747,23 @@ void MetricsWebContentsObserver::WillStartNavigationRequest(
           navigation_handle, chain_size, chain_size_same_url))));
 }
 
+void MetricsWebContentsObserver::OnRequestComplete(
+    content::ResourceType resource_type,
+    bool was_cached,
+    int net_error,
+    int64_t total_received_bytes,
+    int64_t raw_body_bytes) {
+  // For simplicity, only count subresources.
+  if (resource_type == content::RESOURCE_TYPE_MAIN_FRAME &&
+      net_error != net::OK) {
+    return;
+  }
+  if (!committed_load_)
+    return;
+  int64_t bytes = was_cached ? raw_body_bytes : total_received_bytes;

[Bryan McQuade, 2016/08/08 18:53:28]

is raw_body_bytes uncompressed but total_received_bytes compressed? that'd skew
byte counts towards cached responses.

[Charlie Harrison, 2016/08/08 20:55:02]

Great point. I chatted with mmenke@ about this and it seems like if we want
decompressed bytes we have to instrument read calls manually here. Because
that's a decent amount of code for little gain, I'll just punt on the "bytes"
metric for now and go based on # of requests.

+  committed_load_->OnLoadedSubresource(bytes, was_cached);

[Bryan McQuade, 2016/08/08 18:53:28]

are we sure that all resources loaded are for the currently committed load? can
we verify that somehow?

[Charlie Harrison, 2016/08/08 20:55:02]

I think this is reasonably accurate. If there are subresource requests going on
I think it makes sense to attribute them with the current page (i.e. current
committed load). Barring threading race conditions, I think we're okay here.

What kind of verification were you thinking of? 

The alternative approach here would be to do this logic in blink. But I wanted
to fully account for OOPIF, and subframe loads contribute lots to page loads.

+}
+
 const PageLoadExtraInfo
 MetricsWebContentsObserver::GetPageLoadExtraInfoForCommittedLoad() {
   DCHECK(committed_load_);