Fix gn builds never being clean at symbol_level = 0

chrome/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.
 
 import("//build/config/chrome_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/compiler/pgo/pgo.gni")
 import("//build/config/features.gni")
 import("//build/config/locales.gni")
 import("//build/config/sanitizers/sanitizers.gni")
@@ skipping 34 matching lines @@
   action("reorder_imports") {
     script = "//build/win/reorder-imports.py"
 
     # See comment in chrome_dll.gypi in the hardlink_to_output
     # target for why this cannot be 'initial' like the DLL.
     inputs = [
       "$root_out_dir/initialexe/chrome.exe",
     ]
     outputs = [
       "$root_out_dir/chrome.exe",
-      "$root_out_dir/chrome.exe.pdb",
     ]
+    if (symbol_level != 0) {
+      outputs += [ "$root_out_dir/chrome.exe.pdb" ]
+    }
     args = [
       "-i",
       rebase_path("$root_out_dir/initialexe", root_build_dir),
       "-o",
       rebase_path("$root_out_dir", root_build_dir),
       "-a",
       current_cpu,
     ]
     deps = [
       ":chrome_initial",
@@ skipping 1783 matching lines @@
       "//chrome/app/theme/$branding_path_component/product_logo_48.png",
       "//chrome/tools/build/linux/chrome-wrapper",
       "//third_party/xdg-utils/scripts/xdg-mime",
       "//third_party/xdg-utils/scripts/xdg-settings",
     ]
     outputs = [
       "$root_out_dir/{{source_file_part}}",
     ]
   }
 }