Use valid /prefetch arguments for process launches on Windows. - do not submit

chrome/app/main_dll_loader_win.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 <windows.h>  // NOLINT
 #include <shlwapi.h>  // NOLINT
 #include <stddef.h>
 #include <userenv.h>  // NOLINT
 
 #include "chrome/app/main_dll_loader_win.h"
@@ skipping 46 matching lines @@
 typedef int (*DLL_MAIN)(HINSTANCE, sandbox::SandboxInterfaceInfo*);
 
 typedef void (*RelaunchChromeBrowserWithNewCommandLineIfNeededFunc)();
 
 // Loads |module| after setting the CWD to |module|'s directory. Returns a
 // reference to the loaded module on success, or null on error.
 HMODULE LoadModuleWithDirectory(const base::FilePath& module) {
   ::SetCurrentDirectoryW(module.DirName().value().c_str());
 
   // Get pre-read options from the PreRead field trial.
-  bool trial_no_pre_read = false;
-  bool trial_high_priority = false;
-  bool trial_only_if_cold = false;
-  bool trial_prefetch_virtual_memory = false;
-  startup_metric_utils::GetPreReadOptions(
-      BrowserDistribution::GetDistribution()->GetRegistryPath(),
-      &trial_no_pre_read, &trial_high_priority, &trial_only_if_cold,
-      &trial_prefetch_virtual_memory);
+  int pre_read_options = startup_metric_utils::GetPreReadOptions(
+      BrowserDistribution::GetDistribution()->GetRegistryPath());
 
   // Pre-read the binary to warm the memory caches (avoids a lot of random IO).
-  if (!trial_no_pre_read) {
+  if (!(pre_read_options & startup_metric_utils::NO_PRE_READ)) {
     base::ThreadPriority previous_priority = base::ThreadPriority::NORMAL;
-    if (trial_high_priority) {
+    if (pre_read_options & startup_metric_utils::HIGH_PRIORITY) {
       previous_priority = base::PlatformThread::GetCurrentThreadPriority();
       base::PlatformThread::SetCurrentThreadPriority(
           base::ThreadPriority::DISPLAY);
     }
 
-    if (trial_only_if_cold) {
+    if (pre_read_options & startup_metric_utils::ONLY_IF_COLD) {
       base::MemoryMappedFile module_memory_map;
       const bool map_initialize_success = module_memory_map.Initialize(module);
       DCHECK(map_initialize_success);
       if (!IsMemoryMappedFileWarm(module_memory_map)) {
-        if (trial_prefetch_virtual_memory)
+        if (pre_read_options & startup_metric_utils::PREFETCH_VIRTUAL_MEMORY)
           PreReadMemoryMappedFile(module_memory_map, module);
         else
           PreReadFile(module);
       }
-    } else if (trial_prefetch_virtual_memory) {
+    } else if (pre_read_options &
+               startup_metric_utils::PREFETCH_VIRTUAL_MEMORY) {
       base::MemoryMappedFile module_memory_map;
       const bool map_initialize_success = module_memory_map.Initialize(module);
       DCHECK(map_initialize_success);
       PreReadMemoryMappedFile(module_memory_map, module);
     } else {
       PreReadFile(module);
     }
 
-    if (trial_high_priority)
+    if (pre_read_options & startup_metric_utils::HIGH_PRIORITY)
       base::PlatformThread::SetCurrentThreadPriority(previous_priority);
   }
 
   return ::LoadLibraryExW(module.value().c_str(), nullptr,
                           LOAD_WITH_ALTERED_SEARCH_PATH);
 }
 
 void RecordDidRun(const base::FilePath& dll_path) {
   bool system_level = !InstallUtil::IsPerUserInstall(dll_path);
   GoogleUpdateSettings::UpdateDidRunState(true, system_level);
@@ skipping 275 matching lines @@
   }
 };
 
 MainDllLoader* MakeMainDllLoader() {
 #if defined(GOOGLE_CHROME_BUILD)
   return new ChromeDllLoader();
 #else
   return new ChromiumDllLoader();
 #endif
 }