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

content/public/common/content_switches.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/common/content_switches.h"
 
 namespace switches {
 
 // The number of MSAA samples for canvas2D. Requires MSAA support by GPU to
 // have an effect. 0 disables MSAA.
@@ skipping 379 matching lines @@
 // Enables payloads for received push messages when using the W3C Push API.
 const char kEnablePushMessagePayload[] = "enable-push-message-payload";
 
 // Enable hasPermission() method of the W3C Push API.
 const char kEnablePushMessagingHasPermission[] =
         "enable-push-messaging-has-permission";
 
 // Set options to cache V8 data. (off, preparse data, or code)
 const char kV8CacheOptions[] = "v8-cache-options";
 
+// Signals that the V8 natives file has been transfered to the child process
+// by a file descriptor.
+const char kV8NativesPassedByFD[] = "v8-natives-passed-by-fd";
+
+// Signals that the V8 startup snapshot file has been transfered to the child
+// process by a file descriptor.
+const char kV8SnapshotPassedByFD[] = "v8-snapshot-passed-by-fd";

[James Cook, 2015/04/09 16:27:08]

Is it ever valid to pass just one of these files and not the other?  If they
always go together consider just using a single switch -- it'll make it less
likely for someone to miss one, or pass the same one twice.

[rmcilroy, 2015/04/09 22:14:59]

Currently we will always pass both files, however there is a change in-progress
to generate the snapshot file on-demand, which would mean we would pass the
natives file, but not the snapshot file - this is the reason I made this two
separate switches.

+
 // Enables the CSS multicol implementation that uses the regions implementation.
 const char kEnableRegionBasedColumns[] =
     "enable-region-based-columns";
 
 // Cause the OS X sandbox write to syslog every time an access to a resource
 // is denied by the sandbox.
 const char kEnableSandboxLogging[]          = "enable-sandbox-logging";
 
 // Enables seccomp-bpf support for Android. Requires experimental kernel
 // support. <http://crbug.com/166704>
@@ skipping 564 matching lines @@
 // clashes between different instances of Chrome.
 const char kFontCacheSharedMemSuffix[] = "font-cache-shared-mem-suffix";
 #endif
 
 // Enables the use of NPAPI plugins.
 const char kEnableNpapi[]                   = "enable-npapi";
 
 // Don't dump stuff here, follow the same order as the header.
 
 }  // namespace switches