Update GN files w/ changes needed to make sanitizers work.

third_party/instrumented_libraries/BUILD.gn

 # Copyright 2015 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.
 
 import("//build/config/sanitizers/sanitizers.gni")
 
-prebuilt_available =
-    is_msan && (msan_track_origins == 0 || msan_track_origins == 2)
-
 group("deps") {
   if (use_prebuilt_instrumented_libraries) {
     assert(prebuilt_available,
            "Prebuilt instrumented libraries are only available when " +
                "is_msan = true and msan_track_origins = {0, 2}")
     deps = [
       ":prebuilt",
     ]
+    data_deps = [
+      ":prebuilt",
+    ]
   }
 }
 
-if (prebuilt_available) {
+if (prebuilt_instrumented_libraries_available) {
   group("prebuilt") {
     visibility = [ ":deps" ]
-    all_dependent_configs = [ ":prebuilt_link_helper" ]
+
     deps = [
       ":extract_prebuilt_instrumented_libraries",
     ]
+    data_deps = [
+      ":extract_prebuilt_instrumented_libraries",
+    ]
   }
 
   if (is_msan) {
     sanitizer_type = "msan"
     if (msan_track_origins == 0) {
       archive_prefix = "msan-no-origins"
     } else if (msan_track_origins == 2) {
       archive_prefix = "msan-chained-origins"
     }
   }
 
   # TODO(GYP): scripts/download_binaries.py uses GYP_DEFINES to decide whether
   # to download the archives extracted here.
   # Note: This requires a clobber whenever Ubuntu version changes.
   action("extract_prebuilt_instrumented_libraries") {
     visibility = [ ":prebuilt" ]
     script = "scripts/unpack_binaries.py"
     depfile = "$target_out_dir/$archive_prefix.d"
     args = [
       archive_prefix,
       rebase_path("binaries"),
       rebase_path(root_build_dir + "/instrumented_libraries_prebuilt"),
       rebase_path(target_out_dir, root_build_dir),
     ]
     outputs = [
       "$target_out_dir/$archive_prefix.txt",
     ]
+    data = [
+      "$root_out_dir/instrumented_libraries_prebuilt/",
+    ]
   }
 
-  config("prebuilt_link_helper") {
-    visibility = [ ":prebuilt" ]
+  config("prebuilt_ldflags") {
     ldflags = [
       # Add a relative RPATH entry to Chromium binaries. This puts instrumented
       # DSOs before system-installed versions in library search path.
       "-Wl,-R,\$ORIGIN/instrumented_libraries_prebuilt/$sanitizer_type/lib",
       "-Wl,-z,origin",
     ]
   }
 }
 # TODO(GYP): Support building instrumented libraries from source.