Use command line to signal whether a child process was passed V8 snapshot files via file descriptor

content/app/content_main_runner.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 "content/public/app/content_main_runner.h"
 
 #include <stdlib.h>
 
 #include "base/allocator/allocator_extension.h"
 #include "base/at_exit.h"
@@ skipping 682 matching lines @@
     } else {
       CHECK(base::i18n::InitializeICU());
     }
 #else
     CHECK(base::i18n::InitializeICU());
 #endif  // OS_ANDROID
 
 #if defined(V8_USE_EXTERNAL_STARTUP_DATA)
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
 #if !defined(OS_ANDROID)
-    // kV8NativesDataDescriptor and kV8SnapshotDataDescriptor are shared with
-    // child processes. On Android they are set in
+    // kV8NativesDataDescriptor and kV8SnapshotDataDescriptor could be shared
+    // with child processes via file descriptors. On Android they are set in
     // ChildProcessService::InternalInitChildProcess, otherwise set them here.
-    if (!process_type.empty() && process_type != switches::kZygoteProcess
-        && process_type != "service") {
+    if (command_line.HasSwitch(switches::kV8NativesPassedByFD)) {
       g_fds->Set(
           kV8NativesDataDescriptor,
           kV8NativesDataDescriptor + base::GlobalDescriptors::kBaseDescriptor);
+    }
+    if (command_line.HasSwitch(switches::kV8SnapshotPassedByFD)) {
       g_fds->Set(
           kV8SnapshotDataDescriptor,
           kV8SnapshotDataDescriptor + base::GlobalDescriptors::kBaseDescriptor);
     }
 #endif  // !OS_ANDROID
     int v8_natives_fd = g_fds->MaybeGet(kV8NativesDataDescriptor);
     int v8_snapshot_fd = g_fds->MaybeGet(kV8SnapshotDataDescriptor);
     if (v8_natives_fd != -1 && v8_snapshot_fd != -1) {
       auto v8_natives_region = g_fds->GetRegion(kV8NativesDataDescriptor);
       auto v8_snapshot_region = g_fds->GetRegion(kV8SnapshotDataDescriptor);
@@ skipping 113 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(ContentMainRunnerImpl);
 };
 
 // static
 ContentMainRunner* ContentMainRunner::Create() {
   return new ContentMainRunnerImpl();
 }
 
 }  // namespace content