[WebView] Reorganize all of the WebView Shell apks into their own dir.

BUILD.gn

 # Copyright (c) 2013 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.
 
 # This is the root build file for GN. GN will start processing by loading this
 # file, and recursively load all dependencies until all dependencies are either
 # resolved or known not to exist (which will cause the build to fail). So if
 # you add a new build file, there must be some path of dependencies from this
 # file to your new one or GN won't know about it.
 
@@ skipping 291 matching lines @@
         "//components/cronet/android:cronet_test_apk",
         "//components/cronet/android:cronet_test_instrumentation_apk",
         "//components/cronet/android:cronet_unittests",
       ]
     }
 
     if (!is_chromecast) {
       deps += [
         "//android_webview",
         "//android_webview/test",
-        "//android_webview/tools",
+        "//android_webview/tools/system_webview_shell",
         "//chrome/android:chrome_junit_tests",
         "//chrome/android:chrome_public_apk",
         "//chrome/android:chrome_public_test_apk",
         "//chrome/test/chromedriver/test/webview_shell:chromedriver_webview_shell_apk",
         "//content/shell/android:content_shell_test_apk",
         "//third_party/custom_tabs_client:custom_tabs_client_example_apk",
       ]
     }
 
     if (target_cpu != "x64") {
@@ skipping 575 matching lines @@
   assert(target_name != "")  # Mark as used.
   sources = invoker.actual_sources
   assert(
       sources == invoker.actual_sources,
       "Do not use a platform name in your output directory (found \"$root_build_dir\"). http://crbug.com/548283")
 }
 
 assert_valid_out_dir("_unused") {
   actual_sources = [ "$root_build_dir/foo" ]
 }