macOS V2 Sandbox: Add feature for GPU sandbox.

This adds a new feature flag to test the V2 GPU sandbox, the last
process type which must be converted.

Bug: 915934
Change-Id: I5808930e29920adc3cc275748a6e027c6e66dc00
Reviewed-on: https://chromium-review.googlesource.com/c/1379218
Reviewed-by: Avi Drissman <[email protected]>
Reviewed-by: Steven Holte <[email protected]>
Reviewed-by: Robert Sesek <[email protected]>
Commit-Queue: Greg Kerr <[email protected]>
Cr-Commit-Position: refs/heads/master@{#617352}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index fc31320c..215ada9 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -2222,6 +2222,9 @@
      SINGLE_VALUE_TYPE(switches::kTrySupportedChannelLayouts)},
 #endif  // OS_WIN
 #if defined(OS_MACOSX)
+    {"mac-v2-gpu-sandbox", flag_descriptions::kMacV2GPUSandboxName,
+     flag_descriptions::kMacV2GPUSandboxDescription, kOsMac,
+     FEATURE_VALUE_TYPE(features::kMacV2GPUSandbox)},
     {"mac-views-task-manager", flag_descriptions::kMacViewsTaskManagerName,
      flag_descriptions::kMacViewsTaskManagerDescription, kOsMac,
      FEATURE_VALUE_TYPE(features::kViewsTaskManager)},