GN + Android: extract android_standalone_library rule.

This patch extracts the rule needed to produce a standalone .dex.jar for
a set of Java dependencies into a separate rule. This allows to package
any android library into a standalone .dex.jar file without affecting
the target being packaged.

BUG=437290

Review URL: https://codereview.chromium.org/778093004

Cr-Original-Commit-Position: refs/heads/master@{#307575}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 7d7c32ec12774eaf22c901194ff9f788a1dcc9b2

android/gyp/write_build_config.py

@@ -95,13 +95,14 @@ def main(argv):
 
 
   if not options.type in [
-      'java_library', 'android_resources', 'android_apk']:
+      'java_library', 'android_resources', 'android_apk', 'deps_dex']:
     raise Exception('Unknown type: <%s>' % options.type)
 
   required_options = ['build_config'] + {
       'java_library': ['jar_path'],
       'android_resources': ['resources_zip'],
-      'android_apk': ['jar_path', 'dex_path', 'resources_zip']
+      'android_apk': ['jar_path', 'dex_path', 'resources_zip'],
+      'deps_dex': ['dex_path']
     }[options.type]
 
   if options.native_libs:
@@ -213,10 +214,8 @@ def main(argv):
         c['package_name'] for c in all_resources_deps if 'package_name' in c]
 
 
-  # Dependencies for the final dex file of an apk or the standalone .dex.jar
-  # output of a library.
-  if options.type == 'android_apk' or (options.type == "java_library"
-                                       and options.supports_android):
+  # Dependencies for the final dex file of an apk or a 'deps_dex'.
+  if options.type in ['android_apk', 'deps_dex']:
     config['final_dex'] = {}
     dex_config = config['final_dex']
     # TODO(cjhopman): proguard version

config/android/internal_rules.gni

@@ -66,12 +66,13 @@ template("dex") {
     testonly = invoker.testonly
   }
 
-  assert(defined(invoker.sources))
   assert(defined(invoker.output))
   action(target_name) {
     script = "//build/android/gyp/dex.py"
     depfile = "$target_gen_dir/$target_name.d"
-    sources = invoker.sources
+    if (defined(invoker.sources)) {
+      sources = invoker.sources
+    }
     outputs = [
       depfile,
       invoker.output,
@@ -103,7 +104,9 @@ template("dex") {
       args += invoker.args
     }
 
-    args += rebase_path(invoker.sources, root_build_dir)
+    if (defined(invoker.sources)) {
+      args += rebase_path(invoker.sources, root_build_dir)
+    }
   }
 }
 
@@ -163,7 +166,7 @@ template("write_build_config") {
   build_config = invoker.build_config
 
   assert(type == "android_apk" || type == "java_library" ||
-         type == "android_resources")
+         type == "android_resources" || type == "deps_dex")
 
   action(target_name) {
     script = "//build/android/gyp/write_build_config.py"
@@ -201,11 +204,12 @@ template("write_build_config") {
     is_java_library = type == "java_library"
     is_apk = type == "android_apk"
     is_android_resources = type == "android_resources"
+    is_deps_dex = type == "deps_dex"
 
-    supports_android = is_apk || is_android_resources ||
+    supports_android = is_apk || is_android_resources || is_deps_dex ||
                        (is_java_library && defined(invoker.supports_android) &&
                         invoker.supports_android)
-    requires_android = is_apk || is_android_resources ||
+    requires_android = is_apk || is_android_resources || is_deps_dex ||
                        (is_java_library && defined(invoker.requires_android) &&
                         invoker.requires_android)
 
@@ -216,6 +220,7 @@ template("write_build_config") {
     assert(is_java_library || true)
     assert(is_apk || true)
     assert(is_android_resources || true)
+    assert(is_deps_dex || true)
 
     if (is_java_library || is_apk) {
       args += [
@@ -224,7 +229,7 @@ template("write_build_config") {
       ]
     }
 
-    if (is_apk || (is_java_library && supports_android)) {
+    if (is_apk || is_deps_dex || (is_java_library && supports_android)) {
       args += [
         "--dex-path",
         rebase_path(invoker.dex_path, root_build_dir),
@@ -898,22 +903,6 @@ template("java_library_impl") {
       ]
       output = _dex_path
     }
-
-    if (defined(invoker.standalone_dex_path)) {
-      _final_deps += [ ":${_template_name}__standalone_dex" ]
-      _rebased_build_config = rebase_path(_build_config, root_build_dir)
-      dex("${_template_name}__standalone_dex") {
-        sources = [
-          _jar_path,
-        ]
-        inputs = [
-          _build_config,
-        ]
-        output = invoker.standalone_dex_path
-        dex_arg_key = "${_rebased_build_config}:final_dex:dependency_dex_files"
-        args = [ "--inputs=@FileArg($dex_arg_key)" ]
-      }
-    }
   }
 
   group(target_name) {
@@ -1061,3 +1050,25 @@ template("copy_ex") {
     }
   }
 }
+
+# Produces a single .dex.jar out of a set of Java dependencies.
+template("deps_dex") {
+  build_config = "$target_gen_dir/${target_name}.build_config"
+  write_build_config("${target_name}__build_config") {
+    type = "deps_dex"
+    deps = invoker.deps
+
+    build_config = build_config
+    dex_path = invoker.dex_path
+  }
+
+  rebased_build_config = rebase_path(build_config, root_build_dir)
+  dex(target_name) {
+    inputs = [
+      build_config,
+    ]
+    output = invoker.dex_path
+    dex_arg_key = "${rebased_build_config}:final_dex:dependency_dex_files"
+    args = [ "--inputs=@FileArg($dex_arg_key)" ]
+  }
+}

config/android/rules.gni

@@ -922,8 +922,6 @@ template("java_prebuilt") {
 #
 #   dex_path: If set, the resulting .dex.jar file will be placed under this
 #     path.
-#   standalone_dex_path: If set, a standalone .dex.jar containing the code from
-#     the library and all dependencies will be placed under this path.
 #
 #
 # Example
@@ -986,9 +984,6 @@ template("android_library") {
     if (defined(invoker.dex_path)) {
       dex_path = invoker.dex_path
     }
-    if (defined(invoker.standalone_dex_path)) {
-      standalone_dex_path = invoker.standalone_dex_path
-    }
 
     supports_android = true
     requires_android = true
@@ -1005,6 +1000,20 @@ template("android_library") {
   }
 }
 
+# Declare a target that packages a set of Java dependencies into a standalone
+# .dex.jar.
+#
+# Variables
+#   deps: specifies the dependencies of this target. Android libraries in deps
+#     will be packaged into the resulting .dex.jar file.
+#   dex_path: location at which the output file will be put
+template("android_standalone_library") {
+  deps_dex(target_name) {
+    deps = invoker.deps
+    dex_path = invoker.dex_path
+  }
+}
+
 # Declare an Android library target for a prebuilt jar
 #
 # This target creates an Android library containing java code and Android