Rename source_prereqs to inputs in the GN build.

build/secondary/third_party/trace-viewer/BUILD.gn

 # Copyright 2014 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.
 
 tracing_html_files = [
   "trace_viewer/about_tracing/profiling_view.html",
   "trace_viewer/tracing/record_selection_dialog.html",
   "trace_viewer/tracing/sampling_summary_side_panel.html",
   "trace_viewer/tracing/time_summary_side_panel.html",
   "trace_viewer/tracing/input_latency_side_panel.html",
@@ skipping 289 matching lines @@
   "third_party/tvcm/src/tvcm/images/ui-states.png",
 ]
 
 # TODO: ideally this would go into the target_gen_dir, but this requires some
 # changes to the scripts that process them.
 output_resource_dir = "$root_gen_dir/content/browser/tracing"
 
 action("generate_about_tracing") {
   script = "trace_viewer/build/generate_about_tracing_contents"
 
-  source_prereqs = tracing_html_files + tracing_css_files + tracing_js_files +
+  inputs = tracing_html_files + tracing_css_files + tracing_js_files +
     tracing_img_files
   outputs = [
     "$output_resource_dir/about_tracing.js",
     "$output_resource_dir/about_tracing.html",
   ]
 
   args = [
     "--outdir", rebase_path(output_resource_dir, root_build_dir),
   ]
 }