[fuchsia] Update allowed config command-line arguments.

Temporarily relax the implementation to tolerate the presence of
unrecognized command-line parameters in the config file.

Allow some additional command-line options to be passed through:
  --enable-features
  --enable-low-end-device-mode
  --force-gpu-mem-available-mb

Bug: 1020358, 1023012, 1020698, 1032439
Change-Id: I68799a8e1f6f1ef96df29b22e73efc9df11868db
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1954540
Commit-Queue: Wez <wez@chromium.org>
Auto-Submit: Wez <wez@chromium.org>
Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#723280}

fuchsia/engine/context_provider_impl.cc

@@ -149,6 +149,9 @@ bool MaybeAddCommandLineArgsFromConfig(const base::Value& config,
     return true;
 
   static const base::StringPiece kAllowedArgs[] = {
+      switches::kEnableFeatures,
+      switches::kEnableLowEndDeviceMode,
+      switches::kForceGpuMemAvailableMb,
       switches::kRendererProcessLimit,
       switches::kMinHeightForGpuRasterTile,
   };
@@ -156,13 +159,22 @@ bool MaybeAddCommandLineArgsFromConfig(const base::Value& config,
   for (const auto& arg : args->DictItems()) {
     if (!base::Contains(kAllowedArgs, arg.first)) {
       LOG(ERROR) << "Unknown command-line arg: " << arg.first;
-      return false;
+      // TODO(https://crbug.com/1032439): Return false here once we are done
+      // experimenting with memory-related command-line options.
+      continue;
     }
     if (!arg.second.is_string()) {
       LOG(ERROR) << "Config command-line arg must be a string: " << arg.first;
       return false;
     }
     command_line->AppendSwitchNative(arg.first, arg.second.GetString());
+
+    // TODO(https://crbug.com/1023012): enable-low-end-device-mode currently
+    // fakes 512MB total physical memory, which triggers RGB4444 textures,
+    // which
+    // we don't yet support.
+    if (arg.first == switches::kEnableLowEndDeviceMode)
+      command_line->AppendSwitch(switches::kDisableRGBA4444Textures);
   }
 
   return true;

fuchsia/engine/context_provider_impl_unittest.cc

@@ -408,16 +408,17 @@ TEST(ContextProviderImplConfigTest, WithConfigWithDisallowedCommandLineArgs) {
   ContextProviderImpl context_provider;
   context_provider.set_config_for_test(std::move(config_dict));
   context_provider.SetLaunchCallbackForTest(
-      base::BindLambdaForTesting([&](const base::CommandLine& command,
-                                     const base::LaunchOptions& options) {
-        ADD_FAILURE();
+      base::BindLambdaForTesting([&loop](const base::CommandLine& command,
+                                         const base::LaunchOptions& options) {
+        EXPECT_FALSE(command.HasSwitch("kittens-are-nice"));
         loop.Quit();
         return base::Process();
       }));
 
   fuchsia::web::ContextPtr context;
   context.set_error_handler([&loop](zx_status_t status) {
-    EXPECT_EQ(status, ZX_ERR_INTERNAL);
+    ZX_LOG(ERROR, status);
+    ADD_FAILURE();
     loop.Quit();
   });
   context_provider.Create(BuildCreateContextParams(), context.NewRequest());