Add input dependencies on installer test scripts

chrome/installer/mini_installer/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/features.gni")
 import("//build/config/ui.gni")
 import("//build_overrides/v8.gni")
+import("//chrome/test/mini_installer/mini_installer_test.gni")
 import("//chrome/version.gni")
 import("//third_party/icu/config.gni")
 import("//ui/base/ui_features.gni")
 
 config("mini_installer_compiler_flags") {
   # Disable buffer security checking.
   cflags = [ "/GS-" ]
 }
 
 source_set("lib") {
@@ skipping 13 matching lines @@
     "mini_string.cc",
     "mini_string.h",
     "pe_resource.cc",
     "pe_resource.h",
     "regkey.cc",
     "regkey.h",
   ]
 
   configs += [ ":mini_installer_compiler_flags" ]
 
-  deps = [
-    #"test_installer_sentinel",  TODO(GYP) bug 521052.
-  ]
+  # This input dependency on the mini installer test Python files will force a
+  # recompilation when any of the Python files have changed. This will then
+  # invalidate the build and trigger running the test on the bots even when
+  # no other Chrome files have changed. These have to be inputs rather than a
+  # dependency because a dependency won't actually trigger recompiles in
+  # incremental build cases unless a source file actually references one of the
+  # dependency outputs.
+  inputs = mini_installer_test_files
 }
 
 process_version("version") {
   template_file = "mini_installer_exe_version.rc.version"
   output = "$target_gen_dir/mini_installer_version.rc"
 }
 
 source_set("unit_tests") {
   testonly = true
 
@@ skipping 163 matching lines @@
     args = [
       "--out",
       "$target_name.exe",
     ]
     deps = [
       ":mini_installer",
       "//chrome/installer/test:alternate_version_generator",
     ]
   }
 }