[WebView] Add an isolate file to run the WebView Layout tests.

android_webview/system_webview_shell_layout_test_apk_run.isolate

+# Copyright 2016 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.
+{
+  'includes': [
+    '../build/android/android.isolate',
+  ],
+  'variables': {
+    'command': [
+      '<(PRODUCT_DIR)/bin/run_system_webview_shell_layout_test_apk',
+      '--enable-platform-mode',
+      '-e', 'local',
+      '--additional-apk', '<(PRODUCT_DIR)/apks/SystemWebView.apk',

[jbudorick, 2016/03/12 01:27:29]

neither this nor the following line should be necessary. if they are, then the
system_webview_shell_layout_test_apk target isn't configured correctly w/ the
generated test runner script.

+      '--apk-under-test', '<(PRODUCT_DIR)/apks/SystemWebViewShell.apk',
+      '--logcat-output-dir', '${ISOLATED_OUTDIR}/logcats',
+    ],
+    'files': [
+      '../third_party/proguard/lib/proguard.jar',
+      '<(PRODUCT_DIR)/host_forwarder',
+      '<(PRODUCT_DIR)/forwarder_dist/',
+      '<(PRODUCT_DIR)/apks/SystemWebView.apk',
+      '<(PRODUCT_DIR)/apks/SystemWebViewShell.apk',
+      '<(PRODUCT_DIR)/apks/SystemWebViewShellLayoutTest.apk',
+      '<(PRODUCT_DIR)/bin/run_system_webview_shell_layout_test_apk',
+      '<(PRODUCT_DIR)/test.lib.java/SystemWebViewShellLayoutTest.jar',
+      'system_webview_shell_test_apk.isolate',
+      'tools/WebViewShell/test/',
+    ]
+  },
+}