Clean up NaCl's SCons build.

ppapi/native_client/chrome_main.scons

Index: ppapi/native_client/chrome_main.scons
diff --git a/ppapi/native_client/chrome_main.scons b/ppapi/native_client/chrome_main.scons
index 36b989e1583dba49194de6ed96feda41e174e789..8d72327b751f5faf531f24c0f1a6447cf37030ec 100644
--- a/ppapi/native_client/chrome_main.scons
+++ b/ppapi/native_client/chrome_main.scons
@@ -52,7 +52,6 @@ ppapi_scons_files['irt_variant_test_scons_files'] = ExtendFileList(
         # Disabled by Brad Chen 4 Sep to try to green Chromium
         # nacl_integration tests
         #'tests/nacl_browser/fault_injection/nacl.scons',
-        'tests/nacl.scons',
         'tests/nacl_browser/pnacl_client_translator/nacl.scons',
     ])
 
@@ -84,44 +83,30 @@ def GetHeadlessPrefix(env):
 pre_base_env.AddMethod(GetHeadlessPrefix)
 
 
-pre_base_env['CHROME_DOWNLOAD_DIR'] = \
-    pre_base_env.Dir(ARGUMENTS.get('chrome_binaries_dir', '#chromebinaries'))
+# A fake file to depend on if a path to Chrome is not specified.
+no_browser = pre_base_env.File('chrome_browser_path_not_specified')
 
-def ChromeBinaryArch(env):
-  arch = env['BUILD_FULLARCH']
-  # Currently there are no 64-bit Chrome binaries for Windows or Mac OS X.
-  if (env.Bit('host_windows') or env.Bit('host_mac')) and arch == 'x86-64':
-    arch = 'x86-32'
-  return arch
 
-pre_base_env.AddMethod(ChromeBinaryArch)
+# SCons attempts to run a test that depends on "no_browser", detect this at
+# runtime and cause a build error.
+def NoBrowserError(target, source, env):
+  print target, source, env
+  print ("***\nYou need to specificy chrome_browser_path=... on the " +
+         "command line to run these tests.\n***\n")
+  return 1
 
+pre_base_env.Append(BUILDERS = {
+    'NoBrowserError': Builder(action=NoBrowserError)
+})
 
-def DownloadedChromeBinary(env):
-  if env.Bit('host_linux'):
-    os_name = 'linux'
-    binary = 'chrome'
-  elif env.Bit('host_windows'):
-    os_name = 'windows'
-    binary = 'chrome.exe'
-  elif env.Bit('host_mac'):
-    os_name = 'mac'
-    binary = 'Chromium.app/Contents/MacOS/Chromium'
-  else:
-    raise Exception('Unsupported OS')
-
-  arch = env.ChromeBinaryArch()
-  return env.File(os.path.join('${CHROME_DOWNLOAD_DIR}',
-                               '%s_%s' % (os_name, arch), binary))
-
-pre_base_env.AddMethod(DownloadedChromeBinary)
+pre_base_env.NoBrowserError([no_browser], [])
 
 
 def ChromeBinary(env):
   if 'chrome_browser_path' in ARGUMENTS:
     return env.File(env.SConstructAbsPath(ARGUMENTS['chrome_browser_path']))
   else:
-    return env.DownloadedChromeBinary()
+    return no_browser
 
 pre_base_env.AddMethod(ChromeBinary)
 
@@ -529,15 +514,6 @@ def PPAPIBrowserTester(env,
       '--url', url,
       # Fail if there is no response for X seconds.
       '--timeout', str(timeout)]
-  if not env.Bit('disable_dynamic_plugin_loading'):
-    command.extend(['--ppapi_plugin', env['TRUSTED_ENV'].GetPPAPIPluginPath()])
-    command.extend(['--sel_ldr', env.GetSelLdr()])
-    bootstrap, _ = env.GetBootstrap()
-    if bootstrap is not None:
-      command.extend(['--sel_ldr_bootstrap', bootstrap])
-  if (not env.Bit('disable_dynamic_plugin_loading') or
-      env.Bit('override_chrome_irt')):
-    command.extend(['--irt_library', env.GetIrtNexe(chrome_irt=True)])
   for dep_file in files:
     command.extend(['--file', dep_file])
   for extension in extensions: