Exclude Observatory assets from PRODUCT build dart, dart_precompiled_runtime

runtime/BUILD.gn

Index: runtime/BUILD.gn
diff --git a/runtime/BUILD.gn b/runtime/BUILD.gn
index f5c13e9615d0456d9d613f247ce89c414817e7dd..f813be13bc57600306cf2bedd4d2a7ad0a25ef62 100644
--- a/runtime/BUILD.gn
+++ b/runtime/BUILD.gn
@@ -4,35 +4,6 @@
 
 import("runtime_args.gni")
 
-declare_args() {
-  # Instead of using is_debug, we introduce a different flag for specifying a
-  # Debug build of Dart so that clients can still use a Release build of Dart
-  # while themselves doing a Debug build.
-  dart_debug = false
-
-  # Set the runtime mode. This affects how the runtime is built and what
-  # features it has. Valid values are:
-  # 'develop' (the default) - VM is built to run as a JIT with all development
-  # features enabled.
-  # 'profile' - The VM is built to run with AOT compiled code with only the
-  # CPU profiling features enabled.
-  # 'release' - The VM is built to run with AOT compiled code with no developer
-  # features enabled.
-  #
-  # These settings are only used for Flutter, at the moment. A standalone build
-  # of the Dart VM should leave this set to "develop", and should set
-  # 'is_debug', 'is_release', or 'is_product'.
-  dart_runtime_mode = "develop"
-
-  # Explicitly set the target architecture in case of precompilation. Leaving
-  # this unspecified results in automatic target architecture detection.
-  # Available options are: arm, arm64, x64, and ia32
-  dart_target_arch = ""
-
-  # The optimization level to use for debug builds.
-  dart_debug_optimization_level = "2"
-}
-
 config("dart_public_config") {
   include_dirs = [ "." ]
 }