Enable deferred free for syzyasan builds behind a feature.

chrome/browser/chrome_browser_main.cc

 // Copyright (c) 2012 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 "chrome/browser/chrome_browser_main.h"
 
 #include <stddef.h>
 #include <stdint.h>
 #include <set>
 #include <string>
@@ skipping 72 matching lines @@
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/host_desktop.h"
 #include "chrome/browser/ui/startup/bad_flags_prompt.h"
 #include "chrome/browser/ui/startup/default_browser_prompt.h"
 #include "chrome/browser/ui/startup/startup_browser_creator.h"
 #include "chrome/browser/ui/uma_browsing_activity_observer.h"
 #include "chrome/browser/ui/webui/chrome_web_ui_controller_factory.h"
 #include "chrome/common/channel_info.h"
 #include "chrome/common/chrome_constants.h"
+#include "chrome/common/chrome_features.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_result_codes.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/crash_keys.h"
 #include "chrome/common/env_vars.h"
 #include "chrome/common/features.h"
 #include "chrome/common/logging_chrome.h"
 #include "chrome/common/net/net_resource_provider.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/profiling.h"
@@ skipping 1072 matching lines @@
     chrome_extra_parts_[i]->PostProfileInit();
 }
 
 void ChromeBrowserMainParts::PreBrowserStart() {
   TRACE_EVENT0("startup", "ChromeBrowserMainParts::PreBrowserStart");
   for (size_t i = 0; i < chrome_extra_parts_.size(); ++i)
     chrome_extra_parts_[i]->PreBrowserStart();
 
   three_d_observer_.reset(new ThreeDAPIObserver());
 
+#if defined(SYZYASAN)
+  // Enable the deferred free mechanism in the syzyasan module, which helps the
+  // performance by deferring some work on the critical path to a background
+  // thread.
+  if (base::FeatureList::IsEnabled(features::kSyzyasanDeferredFree)) {
+    typedef VOID(WINAPI * SyzyasanEnableDeferredFreeThreadFunc)(VOID);
+    HMODULE SyzyasanModuleHandle = ::GetModuleHandle(L"syzyasan_rtl.dll");

[chrisha, 2016/03/17 18:35:28]

euhh... snake_style variable names instead of CamelCase?

[Georges Khalil, 2016/03/17 19:34:39]

Oops, I was looking at Windows code for too long :S

Done.

+    bool success = false;
+    if (SyzyasanModuleHandle) {
+      SyzyasanEnableDeferredFreeThreadFunc EnableDeferredFreeThread =

[chrisha, 2016/03/17 18:35:28]

ditto

[Georges Khalil, 2016/03/17 19:34:39]

Done.

+          reinterpret_cast<SyzyasanEnableDeferredFreeThreadFunc>(
+              ::GetProcAddress(SyzyasanModuleHandle,
+                               "asan_EnableDeferredFreeThread"));
+      if (EnableDeferredFreeThread) {
+        EnableDeferredFreeThread();
+        success = true;
+      }
+    }
+    UMA_HISTOGRAM_BOOLEAN("Syzyasan.DeferredFreeWasEnabled", success);
+  }
+#endif
+
 // Start the tab manager here so that we give the most amount of time for the
 // other services to start up before we start adjusting the oom priority.
 #if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_CHROMEOS)
   g_browser_process->GetTabManager()->Start();
 #endif
 }
 
 void ChromeBrowserMainParts::PostBrowserStart() {
   TRACE_EVENT0("startup", "ChromeBrowserMainParts::PostBrowserStart");
   for (size_t i = 0; i < chrome_extra_parts_.size(); ++i)
@@ skipping 677 matching lines @@
   chromeos::CrosSettings::Shutdown();
 #endif  // defined(OS_CHROMEOS)
 #endif  // defined(OS_ANDROID)
 }
 
 // Public members:
 
 void ChromeBrowserMainParts::AddParts(ChromeBrowserMainExtraParts* parts) {
   chrome_extra_parts_.push_back(parts);
 }