Add a --enable-unsafe-webgpu flag

This flag will controls the "WebGPU" runtime enabled features that
exposes the prototype WebGPU Blink bindings.

BUG=chromium:852089

Change-Id: Id6e718f85eb05045b8b4056a16b6cb966fba3e4a
Reviewed-on: https://chromium-review.googlesource.com/1097608
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568148}

chrome/browser/chromeos/login/chrome_restart_request.cc

@@ -158,6 +158,7 @@ void DeriveCommandLine(const GURL& start_url,
     ::switches::kDisableWebGLImageChromium,
     ::switches::kEnableWebGLImageChromium,
     ::switches::kEnableWebVR,
+    ::switches::kEnableUnsafeWebGPU,
     ::switches::kDisableWebRtcHWDecoding,
     ::switches::kDisableWebRtcHWEncoding,
     ::switches::kOzonePlatform,

content/browser/renderer_host/render_process_host_impl.cc

@@ -2766,6 +2766,7 @@ void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
     switches::kEnableSlimmingPaintV2,
     switches::kEnableThreadedCompositing,
     switches::kEnableTouchDragDrop,
+    switches::kEnableUnsafeWebGPU,
     switches::kEnableUseZoomForDSF,
     switches::kEnableViewport,
     switches::kEnableVtune,

content/child/runtime_features.cc

@@ -204,6 +204,9 @@ void SetRuntimeFeaturesDefaultsAndUpdateFromArgs(
   else
     WebRuntimeFeatures::EnableV8IdleTasks(true);
 
+  if (command_line.HasSwitch(switches::kEnableUnsafeWebGPU))
+    WebRuntimeFeatures::EnableWebGPU(true);
+
   if (command_line.HasSwitch(switches::kEnableWebVR))
     WebRuntimeFeatures::EnableWebVR(true);
 

content/public/common/content_switches.cc

@@ -429,6 +429,9 @@ const char kEnableTracing[]                 = "enable-tracing";
 // The filename to write the output of the test tracing to.
 const char kEnableTracingOutput[]           = "enable-tracing-output";
 
+// Enables unsafe WebGPU support.
+const char kEnableUnsafeWebGPU[] = "enable-unsafe-webgpu";
+
 // Enable screen capturing support for MediaStream API.
 const char kEnableUserMediaScreenCapturing[] =
     "enable-usermedia-screen-capturing";

content/public/common/content_switches.h

@@ -135,6 +135,7 @@ CONTENT_EXPORT extern const char kEnableStrictPowerfulFeatureRestrictions[];
 CONTENT_EXPORT extern const char kEnableThreadedCompositing[];
 CONTENT_EXPORT extern const char kEnableTracing[];
 CONTENT_EXPORT extern const char kEnableTracingOutput[];
+CONTENT_EXPORT extern const char kEnableUnsafeWebGPU[];
 CONTENT_EXPORT extern const char kEnableUserMediaScreenCapturing[];
 CONTENT_EXPORT extern const char kEnableUseZoomForDSF[];
 CONTENT_EXPORT extern const char kEnableViewport[];

third_party/blink/public/platform/web_runtime_features.h

@@ -151,6 +151,7 @@ class WebRuntimeFeatures {
   BLINK_PLATFORM_EXPORT static void EnableWebBluetooth(bool);
   BLINK_PLATFORM_EXPORT static void EnableWebGLDraftExtensions(bool);
   BLINK_PLATFORM_EXPORT static void EnableWebGLImageChromium(bool);
+  BLINK_PLATFORM_EXPORT static void EnableWebGPU(bool);
   BLINK_PLATFORM_EXPORT static void EnableWebNfc(bool);
   BLINK_PLATFORM_EXPORT static void EnableWebShare(bool);
   BLINK_PLATFORM_EXPORT static void EnableWebUsb(bool);

third_party/blink/renderer/platform/exported/web_runtime_features.cc

@@ -368,6 +368,10 @@ void WebRuntimeFeatures::EnableWebShare(bool enable) {
   RuntimeEnabledFeatures::SetWebShareEnabled(enable);
 }
 
+void WebRuntimeFeatures::EnableWebGPU(bool enable) {
+  RuntimeEnabledFeatures::SetWebGPUEnabled(enable);
+}
+
 void WebRuntimeFeatures::EnableWebVR(bool enable) {
   RuntimeEnabledFeatures::SetWebVREnabled(enable);
 }

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -1319,6 +1319,15 @@
     {
       name: "WebGLImageChromium",
     },
+    // WebGPU adds a large attack surface area to the GPU process and allows
+    // running arbitrary programs on the GPU (compute shaders), which may
+    // perform arbitrary read/writes of GPU memory if not properly sandboxed.
+    // That's why it is marked as "test" and not enabled as part of the
+    // --enable-experimental-web-platform-features flag.
+    {
+      name: "WebGPU",
+      status: "test",
+    },
     {
       name: "WebLocksAPI",
       origin_trial_feature_name: "WebLocksAPI",