Adding DRP specfic UMA for FirstContentfulPaint

chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc

Index: chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
diff --git a/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc b/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
index d42d630f9c8d14e758fb3f744990e1822cbb494e..1878aee688be65719d2603b3233608e559243c0f 100644
--- a/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
+++ b/chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.cc
@@ -22,35 +22,38 @@
 #include "chrome/browser/download/download_resource_throttle.h"
 #include "chrome/browser/mod_pagespeed/mod_pagespeed_metrics.h"
 #include "chrome/browser/net/resource_prefetch_predictor_observer.h"
 #include "chrome/browser/plugins/plugin_prefs.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "chrome/browser/prerender/prerender_manager_factory.h"
 #include "chrome/browser/prerender/prerender_resource_throttle.h"
 #include "chrome/browser/prerender/prerender_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_io_data.h"
+#include "chrome/browser/renderer_host/chrome_navigation_data.h"
 #include "chrome/browser/renderer_host/safe_browsing_resource_throttle.h"
 #include "chrome/browser/renderer_host/thread_hop_resource_throttle.h"
 #include "chrome/browser/safe_browsing/safe_browsing_service.h"
 #include "chrome/browser/signin/chrome_signin_helper.h"
 #include "chrome/browser/tab_contents/tab_util.h"
 #include "chrome/browser/ui/login/login_handler.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/features.h"
 #include "chrome/common/url_constants.h"
 #include "components/content_settings/core/browser/host_content_settings_map.h"
+#include "components/data_reduction_proxy/core/browser/data_reduction_proxy_data.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data.h"
 #include "components/google/core/browser/google_util.h"
 #include "components/policy/core/common/cloud/policy_header_io_helper.h"
 #include "components/variations/net/variations_http_headers.h"
 #include "content/public/browser/browser_thread.h"
+#include "content/public/browser/navigation_data.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/plugin_service.h"
 #include "content/public/browser/plugin_service_filter.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/resource_context.h"
 #include "content/public/browser/resource_dispatcher_host.h"
 #include "content/public/browser/resource_request_info.h"
 #include "content/public/browser/service_worker_context.h"
 #include "content/public/browser/stream_info.h"
@@ -715,10 +718,28 @@ bool ChromeResourceDispatcherHostDelegate::ShouldEnableLoFiMode(
     return data_reduction_proxy_io_data->ShouldEnableLoFiMode(url_request);
   return false;
 }
 
 // static
 void ChromeResourceDispatcherHostDelegate::
     SetExternalProtocolHandlerDelegateForTesting(
     ExternalProtocolHandler::Delegate* delegate) {
   g_external_protocol_handler_delegate = delegate;
 }
+
+content::NavigationData*
+ChromeResourceDispatcherHostDelegate::GetNavigationData(
+    net::URLRequest* request) const {
+  ChromeNavigationData* data =
+      ChromeNavigationData::GetDataAndCreateIfNecessary(request);
+  if (request) {
+    data_reduction_proxy::DataReductionProxyData* data_reduction_proxy_data =
+        data_reduction_proxy::DataReductionProxyData::GetData(*request);
+    // DeepCopy the DataReductionProxyData from the URLRequest to prevent the
+    // URLRequest and DataReductionProxyData from both having ownership of the
+    // same object. This copy will be shortlived as it will be deep copied again
+    // when content makes a clone of NavigationData for the UI thread.
+    if (data_reduction_proxy_data)
+      data->SetDataReductionProxyData(data_reduction_proxy_data->DeepCopy());

[mmenke, 2016/05/06 18:59:36]

This seems worse than the last iteration - we're reusing ChromeNavigationData,
but any time it's accessed, we overwrite its DataReductionProxyData.  I hadn't
realized you were intended to copy the DRP data here.

Oh well - I'll just defer to nasko on this one.

[RyanSturm, 2016/05/06 20:55:44]

This method wasn't intended to be called more than once. I see your concern.
Instead of DeepCopying, it can copy the state from one to the other if
ChromeNavigationData already has a DataReductionProxyData. I'm not sure if that
is the approach we want. If we expected this to get called a few times, and the
DeepCopy does become expensive, it might be.

If SupportsUserData used ref counting instead of unique_ptr, we could just keep
the DataReductionProxyData in sync through that mechanism, but without the ref
counting it just isn't feasible.

Perhaps for clarity, this method should be renamed, CreateNavigationData, but
that also doesn't necessarily seem like the best approach due to the fact that
it might not create a new one. MaybeCreateNavigationDataForURLRequest? I'm
really not sure what the best approach is.

+  }
+  return data;
+}