Use a valid /prefetch argument when launching a process.

The /prefetch:# argument that is currently added to the command line of
processes launched with content::StartSandboxedProcess is ignored by
Windows because # doesn't respect the [1, 8] constraint.

This CL ensures that a valid /prefetch:# argument is used for every
process launch (except when the feature is disabled by the PreRead
field trial).

BUG=577698

Review URL: https://codereview.chromium.org/1612663002

Cr-Commit-Position: refs/heads/master@{#373241}
(cherry picked from commit 343068c41c299e65a87d935654f0b81a9935250f)

Conflicts:
	chrome/service/DEPS

TBR=gab@chromium.org

Review URL: https://codereview.chromium.org/1727983002 .

Cr-Commit-Position: refs/branch-heads/2623@{#484}
Cr-Branched-From: 92d77538a86529ca35f9220bd3cd512cbea1f086-refs/heads/master@{#369907}

10 files changed, 75 insertions, 25 deletions

diff --git a/components/crash.gypi b/components/crash.gypi
index 00ee69c..8ef86ad 100644
--- a/components/crash.gypi
+++ b/components/crash.gypi
@@ -217,6 +217,13 @@
           ],
           'defines': ['CRASH_IMPLEMENTATION'],
           'conditions': [
+            ['OS=="win"', {
+              'dependencies': [
+                # TODO(fdoray): Remove this once the PreRead field trial has
+                # expired. crbug.com/577698
+                '<(DEPTH)/components/components.gyp:startup_metric_utils_common',
+              ],
+            }],
             ['OS=="mac" or OS=="win"', {
               'dependencies': [
                 '../third_party/crashpad/crashpad/client/client.gyp:crashpad_client',
diff --git a/components/crash/content/app/BUILD.gn b/components/crash/content/app/BUILD.gn
index 52140ce..3def677 100644
--- a/components/crash/content/app/BUILD.gn
+++ b/components/crash/content/app/BUILD.gn
@@ -49,6 +49,13 @@ source_set("app") {
   ]
 
   deps += [ ":lib" ]
+  if (is_win) {
+    deps += [
+      # TODO(fdoray): Remove this once the PreRead field trial has expired.
+      # crbug.com/577698
+      "//components/startup_metric_utils/common",
+    ]
+  }
   if (is_mac || is_win) {
     deps += [ "//third_party/crashpad/crashpad/client" ]
   }
diff --git a/components/crash/content/app/DEPS b/components/crash/content/app/DEPS
index 80bc21a..01c710b 100644
--- a/components/crash/content/app/DEPS
+++ b/components/crash/content/app/DEPS
@@ -3,6 +3,11 @@ include_rules = [
 
   "+content/public/common/content_descriptors.h",
   "+content/public/common/result_codes.h",
+
+  # TODO(fdoray): Remove this once the PreRead field trial has expired.
+  # crbug.com/577698
+  "+components/startup_metric_utils/common/pre_read_field_trial_utils_win.h",
+
   "+third_party/crashpad",
   "+third_party/kasko",
   "+third_party/lss/linux_syscall_support.h",
diff --git a/components/crash/content/app/crashpad_win.cc b/components/crash/content/app/crashpad_win.cc
index 1c241ca..95e53e2 100644
--- a/components/crash/content/app/crashpad_win.cc
+++ b/components/crash/content/app/crashpad_win.cc
@@ -16,6 +16,7 @@
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "components/crash/content/app/crash_reporter_client.h"
+#include "components/startup_metric_utils/common/pre_read_field_trial_utils_win.h"
 #include "third_party/crashpad/crashpad/client/crashpad_client.h"
 #include "third_party/crashpad/crashpad/client/crashpad_info.h"
 #include "third_party/crashpad/crashpad/client/simulate_crash_win.h"
@@ -75,6 +76,13 @@ base::FilePath PlatformCrashpadInitialization(bool initial_client,
       exe_file = exe_dir.Append(FILE_PATH_LITERAL("crashpad_handler.exe"));
     } else {
       arguments.push_back("--type=crashpad-handler");
+
+      if (startup_metric_utils::GetPreReadOptions().use_prefetch_argument) {
+        // The prefetch argument added here has to be documented in
+        // chrome_switches.cc, below the kPrefetchArgument* constants. A
+        // constant can't be used here because crashpad can't depend on Chrome.
+        arguments.push_back("/prefetch:7");
+      }
     }
 
     // TODO(scottmg): See https://crashpad.chromium.org/bug/23.
diff --git a/components/nacl.gyp b/components/nacl.gyp
index a9ed69c..2fd7aba 100644
--- a/components/nacl.gyp
+++ b/components/nacl.gyp
@@ -139,6 +139,13 @@
                 '../sandbox/sandbox.gyp:sandbox_services',
               ]
             }],
+            ['OS=="win"', {
+              'dependencies': [
+                # TODO(fdoray): Remove this once the PreRead field trial has
+                # expired. crbug.com/577698
+                '../components/components.gyp:startup_metric_utils_common',
+              ]
+            }],
           ],
         },
         {
diff --git a/components/nacl/browser/BUILD.gn b/components/nacl/browser/BUILD.gn
index 63c2c9d..9b247f4 100644
--- a/components/nacl/browser/BUILD.gn
+++ b/components/nacl/browser/BUILD.gn
@@ -63,6 +63,14 @@ source_set("browser") {
     data_deps += [ "//components/nacl/loader:helper_nonsfi" ]
   }
 
+  if (is_win) {
+    deps += [
+      # TODO(fdoray): Remove this once the PreRead field trial has expired.
+      # crbug.com/577698
+      "//components/startup_metric_utils/common",
+    ]
+  }
+
   if (is_win && current_cpu == "x86") {
     data_deps += [ "//components/nacl/broker:nacl64" ]
   }
diff --git a/components/nacl/browser/DEPS b/components/nacl/browser/DEPS
index efbdb131..2e1a96b 100644
--- a/components/nacl/browser/DEPS
+++ b/components/nacl/browser/DEPS
@@ -1,4 +1,7 @@
 include_rules = [
+  # TODO(fdoray): Remove this once the PreRead field trial has expired.
+  # crbug.com/577698
+  "+components/startup_metric_utils/common",
   "+components/url_formatter",
   "+content/public/browser",
   "+content/public/test",
diff --git a/components/nacl/browser/nacl_process_host.cc b/components/nacl/browser/nacl_process_host.cc
index aa4f4c5..2ade0f7 100644
--- a/components/nacl/browser/nacl_process_host.cc
+++ b/components/nacl/browser/nacl_process_host.cc
@@ -76,6 +76,7 @@
 #include "base/win/scoped_handle.h"
 #include "components/nacl/browser/nacl_broker_service_win.h"
 #include "components/nacl/common/nacl_debug_exception_handler_win.h"
+#include "components/startup_metric_utils/common/pre_read_field_trial_utils_win.h"
 #include "content/public/common/sandbox_init.h"
 #endif
 
@@ -625,7 +626,12 @@ bool NaClProcessHost::LaunchSelLdr() {
   if (NaClBrowser::GetDelegate()->DialogsAreSuppressed())
     cmd_line->AppendSwitch(switches::kNoErrorDialogs);
 
-  // On Windows we might need to start the broker process to launch a new loader
+#if defined(OS_WIN)
+  if (startup_metric_utils::GetPreReadOptions().use_prefetch_argument)
+    cmd_line->AppendArg(switches::kPrefetchArgumentOther);
+#endif  // defined(OS_WIN)
+
+// On Windows we might need to start the broker process to launch a new loader
 #if defined(OS_WIN)
   if (RunningOnWOW64()) {
     if (!NaClBrokerService::GetInstance()->LaunchLoader(
diff --git a/components/startup_metric_utils/common/pre_read_field_trial_utils_win.cc b/components/startup_metric_utils/common/pre_read_field_trial_utils_win.cc
index a75a81c..dbb32bf 100644
--- a/components/startup_metric_utils/common/pre_read_field_trial_utils_win.cc
+++ b/components/startup_metric_utils/common/pre_read_field_trial_utils_win.cc
@@ -25,12 +25,16 @@ const char kPreReadFieldTrialName[] = "PreRead";
 // annotated with the pre-read group that is actually used during this startup.
 const char kPreReadSyntheticFieldTrialName[] = "SyntheticPreRead";
 
-// Variation names for the PreRead field trial.
+// Variation names for the PreRead field trial. All variations change the
+// default behavior, i.e. the default is the inverse of the variation. Thus,
+// variations that cancel something that is done by default have a negative
+// name.
 const base::char16 kNoPreReadVariationName[] = L"NoPreRead";
 const base::char16 kHighPriorityVariationName[] = L"HighPriority";
 const base::char16 kOnlyIfColdVariationName[] = L"OnlyIfCold";
 const base::char16 kPrefetchVirtualMemoryVariationName[] =
     L"PrefetchVirtualMemory";
+const base::char16 kNoPrefetchArgumentVariationName[] = L"NoPrefetchArgument";
 
 // Registry key in which the PreRead field trial group is stored.
 const base::char16 kPreReadFieldTrialRegistryKey[] = L"\\PreReadFieldTrial";
@@ -45,6 +49,12 @@ base::string16 GetPreReadRegistryPath(
   return product_registry_path + kPreReadFieldTrialRegistryKey;
 }
 
+// Returns true if |key| has a value named |name| which is not zero.
+bool ReadBool(const base::win::RegKey& key, const base::char16* name) {
+  DWORD value = 0;
+  return key.ReadValueDW(name, &value) == ERROR_SUCCESS && value != 0;
+}
+
 }  // namespace
 
 void InitializePreReadOptions(const base::string16& product_registry_path) {
@@ -57,27 +67,13 @@ void InitializePreReadOptions(const base::string16& product_registry_path) {
                               KEY_QUERY_VALUE);
 
   // Set the PreRead field trial's options.
-  struct {
-    const base::char16* name;
-    bool* option;
-  } const variations_mappings[] = {
-      {kNoPreReadVariationName, &g_pre_read_options.no_pre_read},
-      {kHighPriorityVariationName, &g_pre_read_options.high_priority},
-      {kOnlyIfColdVariationName, &g_pre_read_options.only_if_cold},
-      {kPrefetchVirtualMemoryVariationName,
-       &g_pre_read_options.prefetch_virtual_memory},
-  };
-
-  for (const auto& mapping : variations_mappings) {
-    // Set the option variable to true if the corresponding value is found in
-    // the registry. Set to false otherwise (default behavior).
-    DWORD value = 0;
-    if (key.ReadValueDW(mapping.name, &value) == ERROR_SUCCESS) {
-      DCHECK_EQ(1U, value);
-      DCHECK(!*mapping.option);
-      *mapping.option = true;
-    }
-  }
+  g_pre_read_options.pre_read = !ReadBool(key, kNoPreReadVariationName);
+  g_pre_read_options.high_priority = ReadBool(key, kHighPriorityVariationName);
+  g_pre_read_options.only_if_cold = ReadBool(key, kOnlyIfColdVariationName);
+  g_pre_read_options.prefetch_virtual_memory =
+      ReadBool(key, kPrefetchVirtualMemoryVariationName);
+  g_pre_read_options.use_prefetch_argument =
+      !ReadBool(key, kNoPrefetchArgumentVariationName);
 }
 
 PreReadOptions GetPreReadOptions() {
diff --git a/components/startup_metric_utils/common/pre_read_field_trial_utils_win.h b/components/startup_metric_utils/common/pre_read_field_trial_utils_win.h
index cacf4b3..a2aaf4a 100644
--- a/components/startup_metric_utils/common/pre_read_field_trial_utils_win.h
+++ b/components/startup_metric_utils/common/pre_read_field_trial_utils_win.h
@@ -21,8 +21,8 @@ using RegisterPreReadSyntheticFieldTrialCallback =
 
 // The options controlled by the PreRead field trial.
 struct PreReadOptions {
-  // No explicit DLL pre-reading.
-  bool no_pre_read;
+  // Pre-read DLLs explicitly.
+  bool pre_read;
 
   // Pre-read DLLs with a high thread priority.
   bool high_priority;
@@ -32,6 +32,9 @@ struct PreReadOptions {
 
   // Pre-read DLLs using the ::PrefetchVirtualMemory function, if available.
   bool prefetch_virtual_memory;
+
+  // Use a /prefetch argument when launching a process.
+  bool use_prefetch_argument;
 };
 
 // Initializes DLL pre-reading options from the registry.