Make crazy linker work in gn build

content/shell/android/BUILD.gn

 # Copyright 2014 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/android/config.gni")
 import("//build/config/android/rules.gni")
 import("//third_party/icu/config.gni")
 
 generate_jni("content_shell_jni_headers") {
   jni_package = "content/shell"
   sources = [
     "browsertests_apk/src/org/chromium/content_browsertests_apk/ContentBrowserTestsActivity.java",
     "java/src/org/chromium/content_shell/ShellLayoutTestUtils.java",
     "java/src/org/chromium/content_shell/ShellManager.java",
     "java/src/org/chromium/content_shell/ShellMojoTestUtils.java",
     "java/src/org/chromium/content_shell/Shell.java",
   ]
 }
 
 shared_library("libcontent_shell_content_view") {
   testonly = true
   deps = [
     ":content_shell_jni_headers",
     "//content/shell:content_shell_lib",
     "//content/shell:pak",
     "//components/crash/browser",
     "//skia",
     "//media/base/android",
-    "//mojo/android:libsystem_java",
   ]
   sources = [
     "shell_library_loader.cc",
     "shell_library_loader.h",
   ]
   if (is_android_webview_build) {
     ldflags = [
       "-lgabi++",
     ]
   }
@@ skipping 51 matching lines @@
   ]
 
   if (icu_use_data_file) {
     sources += [
       "$root_build_dir/icudtl.dat"
     ]
   }
 }
 
 android_apk("content_shell_apk") {
+  use_chromium_linker = true
   testonly = true
   datadeps = [
     # "//tools/android/forwarder",
   ]
   deps = [
     ":content_shell_apk_resources",
     ":content_shell_java",
     ":content_shell_apk_java",
     ":libcontent_shell_content_view",
     ":copy_content_shell_assets",
@@ skipping 39 matching lines @@
     "//content/public/android:content_javatests",
     "//base:base_javatests",
     "//net/android:net_javatests",
   ]
   datadeps = [
     ":content_shell_apk",
   ]
   apk_name = "ContentShellTest"
   android_manifest = "javatests/AndroidManifest.xml"
 }
+
+if (cpu_arch != "x64" && cpu_arch != "arm64") {
+
+  android_resources("linker_resources") {
+    resource_dirs = [ "linker_test_apk/res" ]
+    android_manifest = "linker_test_apk/AndroidManifest.xml"
+  }
+
+  # GYP: //content/content_tests.gypi:chromium_linker_test_apk
+  android_apk("chromium_linker_test_apk") {
+    testonly = true
+    deps = [
+      ":content_shell_java",
+      ":copy_content_shell_assets",
+      ":linker_resources",
+      ":linker_test",
+      "//base:base_java",
+      "//content/public/android:content_java",
+      "//ui/android:ui_java",
+    ]
+    android_manifest = "linker_test_apk/AndroidManifest.xml"
+    asset_location = content_shell_assets_dir
+    apk_name = "ChromiumLinkerTest"
+    DEPRECATED_java_in_dir = "linker_test_apk/src"
+    native_libs = [
+      "$root_build_dir/lib.stripped/liblinker_test.so"
+    ]
+    use_chromium_linker = true
+    enable_chromium_linker_tests = true
+  }
+
+
+  # GYP: //content/content_tests.gypi:chromium_android_linker_test
+  shared_library("linker_test") {
+    testonly = true
+    sources = [
+      "linker_test_apk/chromium_linker_test_android.cc",
+      "linker_test_apk/chromium_linker_test_linker_tests.cc",
+    ]
+
+    deps = [
+      ":linker_test_jni_headers",
+      "//content/shell:content_shell_lib",
+      # Required to include "content/public/browser/android/compositor.h"
+      # in chromium_linker_test_android.cc :-(
+      "//skia",
+    ]
+  }
+
+  # GYP: //content/content_tests.gypi:chromium_android_linker_test_jni_headers
+  generate_jni("linker_test_jni_headers") {
+    testonly = true
+    jni_package = "content/shell"
+    sources = [
+      "linker_test_apk/src/org/chromium/chromium_linker_test_apk/LinkerTests.java",
+    ]
+  }
+
+} else {
+  group("chromium_linker_test_apk") {

[jamesr, 2014/10/09 19:22:57]

this seems wrong - are people declaring a dependency on chromium_linker_test_apk
when they shouldn't?

[cjhopman, 2014/10/09 20:22:39]

No, they aren't (afaik). The thing is, //BUILD.gn should sort of list all the
top-level targets (it really only needs to list enough that it discovers all the
relevant BUILD.gn files). It doesn't actually need to list
chromium_linker_test_apk (though it will if/when that gets moved into its own
BUILD.gn file). 

Then, the issue is, how do you make that work for a target that is disabled in
certain configurations. We could duplicate the condition enabling it here in
//BUILD.gn, but I don't really like that. We could hoist the condition into a
variable that can be used in both places (which is effectively what we do for
"is_android"-only targets). Or we could do this where we can unconditionally say
that chromium_linker_test_apk is a top-level target and just in some
configurations it is an empty group.

(the other problem that will come up for similar targets is that there might be
other places that we list top-level targets like build recipes, etc).

Alternatively, we could just ignore this for now and not list
chromium_linker_test_apk in the root build file.

Any preference? Other suggestions?

[cjhopman, 2014/10/09 20:47:37]

Done.

+  }
+}