[Tab Metrics] Measure FP, FCP and FMP for Foreground Tab during Session Restore

chrome/browser/sessions/tab_loader.cc

Index: chrome/browser/sessions/tab_loader.cc
diff --git a/chrome/browser/sessions/tab_loader.cc b/chrome/browser/sessions/tab_loader.cc
index 753f4e0493c23ad66dc15e7f1f37a6574ce3f7e1..7fcb263b7782c14525a35daff50bb49e56a964f4 100644
--- a/chrome/browser/sessions/tab_loader.cc
+++ b/chrome/browser/sessions/tab_loader.cc
@@ -13,6 +13,8 @@
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "build/build_config.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/resource_coordinator/tab_manager.h"
 #include "chrome/browser/sessions/session_restore_stats_collector.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_finder.h"
@@ -103,6 +105,11 @@ TabLoader::TabLoader(base::TimeTicks restore_started)
   shared_tab_loader_ = this;
   this_retainer_ = this;
   base::MemoryCoordinatorClientRegistry::GetInstance()->Register(this);
+
+  resource_coordinator::TabManager* tab_manager =
+      g_browser_process->GetTabManager();
+  if (tab_manager)
+    tab_manager->MarkSessionRestoreStarted();

[chrisha, 2017/06/15 19:44:56]

This will fail if their are multiple session restores started across multiple
profiles that overlap. We need a counter for the number of concurrent session
restores that are ongoing.

More likely, we'll need to tag WebContents with a kind of session restore ID so
we know that which session restore a tab is associated with...

 }
 
 TabLoader::~TabLoader() {
@@ -110,6 +117,11 @@ TabLoader::~TabLoader() {
   DCHECK(shared_tab_loader_ == this);
   shared_tab_loader_ = nullptr;
   base::MemoryCoordinatorClientRegistry::GetInstance()->Unregister(this);
+
+  resource_coordinator::TabManager* tab_manager =
+      g_browser_process->GetTabManager();
+  if (tab_manager)
+    tab_manager->MarkSessionRestoreEnded();
 }
 
 void TabLoader::StartLoading(const std::vector<RestoredTab>& tabs) {