Port custom_tabs_client from GYP to GN

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 203 matching lines @@
   }
 
   if (is_android) {
     deps += [
       "//base/android/linker:chromium_android_linker",
       "//build/android/gyp/test:hello_world",
       "//build/android/rezip",
       "//chrome/android:chrome_public_apk",
       "//chrome/android:chrome_public_test_apk",
       "//chrome/test/chromedriver/test/webview_shell:chromedriver_webview_shell_apk",
+      "//third_party/custom_tabs_client:custom_tabs_client_example_apk",

[pasko, 2015/09/29 09:38:58]

this puts custom_tabs_client_example_apk as a dependency to all android target
or I am reading it wrong?

The GYP target does not put itself anywhere except the All target, and also
conditionalized on customtabs==0.

I thought we trying to mirror the logic with GYP, then I am lacking context on
why these particular bits were decided not to be replicated.

Please educate me :)

       "//third_party/errorprone:chromium_errorprone",
       "//tools/android:android_tools",
       "//tools/imagediff($host_toolchain)",
 
       # TODO(GYP): Remove these when the components_unittests work.
       "//components/history/core/test:test",
       "//components/policy:policy_component_test_support",
       "//components/policy:test_support",
       "//components/rappor:test_support",
       "//components/signin/core/browser:test_support",
@@ skipping 700 matching lines @@
       "//ui/views:views_unittests",  # TooltipControllerTest failures
       "//ui/wm:wm_unittests",  # PASSES 4/21/2015
       "//url:url_unittests",  # PASSES 4/17/2015
 
       # TODO(GYP) nacl_integration
       # TODO(GYP) telemetry_perf_unittests
       # TODO(GYP) telemetry_unittests
     ]
   }
 }