[Impeller] Remove unused GN flags.

impeller/tools/args.gni

@@ -9,9 +9,6 @@ declare_args() {
   impeller_debug =
       flutter_runtime_mode == "debug" || flutter_runtime_mode == "profile"
 
-  # Whether the runtime capture/playback system is enabled.
-  impeller_capture = flutter_runtime_mode == "debug"
-
   # Whether the Metal backend is enabled.
   impeller_enable_metal = (is_mac || is_ios) && target_os != "fuchsia"
 
@@ -23,25 +20,12 @@ declare_args() {
   impeller_enable_vulkan = (is_linux || is_win || is_android || is_mac ||
                             enable_unittests) && target_os != "fuchsia"
 
-  # Whether to use a prebuilt impellerc.
-  # If this is the empty string, impellerc will be built.
-  # If it is non-empty, it should be the absolute path to impellerc.
-  impeller_use_prebuilt_impellerc = ""
-
-  # Whether to use a prebuilt scenec.
-  # If this is the empty string, scenec will be built.
-  # If it is non-empty, it should be the absolute path to scenec.
-  impeller_use_prebuilt_scenec = ""
-
   # If enabled, all OpenGL calls will be traced. Because additional trace
   # overhead may be substantial, this is not enabled by default.
   impeller_trace_all_gl_calls = false
 
   # Enable experimental 3D scene rendering.
   impeller_enable_3d = false
-
-  # Enable to get trace statements for canvas usage.
-  impeller_trace_canvas = false
 }
 
 # Arguments that are combinations of other arguments by default but which can

impeller/tools/compiler.gni

@@ -14,34 +14,14 @@ import("//flutter/impeller/tools/args.gni")
 #   invoked once via `compiled_action` or `action`.
 template("_impellerc") {
   if (invoker.single_invocation) {
-    if (impeller_use_prebuilt_impellerc == "") {
-      compiled_action(target_name) {
-        forward_variables_from(invoker, "*")
-        tool = "//flutter/impeller/compiler:impellerc"
-      }
-    } else {
-      action(target_name) {
-        forward_variables_from(invoker, "*", [ "args" ])
-        script = "//build/gn_run_binary.py"
-        impellerc_path =
-            rebase_path(impeller_use_prebuilt_impellerc, root_build_dir)
-        args = [ impellerc_path ] + invoker.args
-      }
+    compiled_action(target_name) {
+      forward_variables_from(invoker, "*")
+      tool = "//flutter/impeller/compiler:impellerc"
     }
   } else {
-    if (impeller_use_prebuilt_impellerc == "") {
-      compiled_action_foreach(target_name) {
-        forward_variables_from(invoker, "*")
-        tool = "//flutter/impeller/compiler:impellerc"
-      }
-    } else {
-      action_foreach(target_name) {
-        forward_variables_from(invoker, "*", [ "args" ])
-        script = "//build/gn_run_binary.py"
-        impellerc_path =
-            rebase_path(impeller_use_prebuilt_impellerc, root_build_dir)
-        args = [ impellerc_path ] + invoker.args
-      }
+    compiled_action_foreach(target_name) {
+      forward_variables_from(invoker, "*")
+      tool = "//flutter/impeller/compiler:impellerc"
     }
   }
 }

impeller/tools/scene.gni

@@ -1,42 +1,27 @@
-# Dispatches to the build or prebuilt scenec depending on the value of
-# the impeller_use_prebuilt_scenec argument. Forwards all variables to
-# compiled_action_foreach or action_foreach as appropriate.
+# Copyright 2013 The Flutter Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
 
 import("//build/compiled_action.gni")
 import("//flutter/impeller/tools/args.gni")
 
-template("_scenec") {
-  if (impeller_use_prebuilt_scenec == "") {
-    compiled_action_foreach(target_name) {
-      forward_variables_from(invoker, "*")
-      tool = "//flutter/impeller/scene/importer:scenec"
-    }
-  } else {
-    action_foreach(target_name) {
-      forward_variables_from(invoker, "*", [ "args" ])
-      script = "//build/gn_run_binary.py"
-      scenec_path = rebase_path(impeller_use_prebuilt_scenec, root_build_dir)
-      args = [ scenec_path ] + invoker.args
-    }
-  }
-}
-
 template("scenec") {
   assert(defined(invoker.geometry), "Geometry input files must be specified.")
   assert(defined(invoker.type),
          "The type of geometry to be parsed (gltf, etc..).")
 
-  _scenec(target_name) {
-    sources = invoker.geometry
-    generated_dir = "$target_gen_dir"
+  compiled_action_foreach(target_name) {
+    tool = "//flutter/impeller/scene/importer:scenec"
 
+    sources = invoker.geometry
     input_type = invoker.type
+
     args = [
       "--input={{source}}",
       "--input-type=$input_type",
     ]
 
-    output = "$generated_dir/{{source_file_part}}.ipscene"
+    output = "$target_gen_dir/{{source_file_part}}.ipscene"
     output_path = rebase_path(output, root_build_dir)
 
     args += [ "--output=$output_path" ]

tools/gn

@@ -719,12 +719,6 @@ def to_gn_args(args):
   if args.enable_impeller_3d:
     gn_args['impeller_enable_3d'] = True
 
-  if args.enable_impeller_trace_canvas:
-    gn_args['impeller_trace_canvas'] = True
-
-  if args.prebuilt_impellerc is not None:
-    gn_args['impeller_use_prebuilt_impellerc'] = args.prebuilt_impellerc
-
   malioc_path = args.malioc_path
   if not malioc_path:
     malioc_path = os.environ.get('MALIOC_PATH')
@@ -1162,27 +1156,13 @@ def parse_args(args):
   )
 
   # Impeller flags.
-  parser.add_argument(
-      '--prebuilt-impellerc',
-      default=None,
-      type=str,
-      help='Absolute path to a prebuilt impellerc. ' +
-      'Do not use this outside of CI or with impellerc from a different engine version.'
-  )
-
   parser.add_argument(
       '--enable-impeller-3d',
       default=False,
       action='store_true',
       help='Enables experimental 3d support.'
   )
 
-  parser.add_argument(
-      '--enable-impeller-trace-canvas',
-      default=False,
-      action='store_true',
-      help='Enables tracing calls to Canvas.'
-  )
   parser.add_argument('--malioc-path', type=str, help='The path to the malioc tool.')
 
   parser.add_argument(