[Android] Define a baseline seccomp-bpf sandbox policy.

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"
 
 #include "base/command_line.h"
 
 namespace switches {
 
@@ skipping 338 matching lines @@
 // Enables accelerated compositing for backgrounds of root layers with
 // background-attachment: fixed. Requires kForceCompositingMode.
 const char kEnableAcceleratedFixedRootBackground[] =
     "enable-accelerated-fixed-root-background";
 
 // Enables accelerated compositing for overflow scroll. Promotes eligible
 // overflow:scroll elements to layers to enable accelerated scrolling for them.
 const char kEnableAcceleratedOverflowScroll[] =
     "enable-accelerated-overflow-scroll";
 
+// Enables seccomp-bpf support for Android. Requires experimental kernel
+// support. <http://crbug.com/166704>
+const char kEnableAndroidSeccompBPF[] = "enable-android-seccomp-bpf";

[jln (very slow on Chromium), 2014/04/09 05:11:07]

Maybe call it kEnableAndroidSeccompFilter for consistency with
kDisableSeccompFilterSandbox ?

I wonder if we shouldn't just have kDisableSeccompFilterSandbox and
kEnableSeccompFilterSandbox (without specifying Android). Then each OS can
implement its own policy of what is the default and let the command line
override that.

[Robert Sesek, 2014/04/09 21:00:58]

Renamed to match kDisableSeccompFilterSandbox. I'm not sure we need something
more generic, since we expect all our Linux flavors to eventually have
seccomp-bpf, right? I imagine this flag will go away once all the stars align,
though we'll keep the disable switch for testing purposes.

[jln (very slow on Chromium), 2014/04/09 21:56:19]

That works, but I still would think that kEnableSeccompFilterSandbox is better.

What I meant is that I don't see the need for per-OS flags here. We can have two
generic flags, each platform can have its own default and use the flags as
appropriate.
For instance, in Linux, we could use this flag to FORCE a seccomp sandbox
(instead of failing silently if it's disabled - which may be a good thing to do
on Chrome OS). I also fear that we may need this flag as we bring-up new
platforms (Aarch64 / MIPS).

[Robert Sesek, 2014/04/09 22:07:54]

Done.

+
 // Enables LCD text.
 const char kEnableLCDText[]                 = "enable-lcd-text";
 
 // Enables experimental feature that maps multiple RenderLayers to
 // one composited layer to avoid pathological layer counts.
 const char kEnableLayerSquashing[] =
     "enable-layer-squashing";
 
 // Turns on extremely verbose logging of accessibility events.
 const char kEnableAccessibilityLogging[]    = "enable-accessibility-logging";
@@ skipping 661 matching lines @@
 
 // Disables support for Core Animation plugins. This is triggered when
 // accelerated compositing is disabled. See http://crbug.com/122430 .
 const char kDisableCoreAnimationPlugins[] =
     "disable-core-animation-plugins";
 #endif
 
 // Don't dump stuff here, follow the same order as the header.
 
 }  // namespace switches