Reland of Add GN build rules to allow java_assertion_enabler to enable Java asserts.

build/config/android/internal_rules.gni

Index: build/config/android/internal_rules.gni
diff --git a/build/config/android/internal_rules.gni b/build/config/android/internal_rules.gni
index 9fd0a518f261e222353af53cdeb4fe6d58a0422a..95e87faab7b5778188cf99ca88d7682b0b02bb0d 100644
--- a/build/config/android/internal_rules.gni
+++ b/build/config/android/internal_rules.gni
@@ -6,6 +6,7 @@
 # Some projects (e.g. V8) do not have non-build directories DEPS'ed in.
 import("//build_overrides/build.gni")
 import("//build/config/android/config.gni")
+import("//build/config/dcheck_always_on.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 
 assert(is_android)
@@ -989,11 +990,12 @@ if (enable_java_templates) {
     _rebased_build_config = rebase_path(_build_config, root_build_dir)
     assert(_rebased_build_config != "" || true)  # Mark used.
 
-    _proguard_preprocess =
-        defined(invoker.proguard_preprocess) && invoker.proguard_preprocess
     _input_jar_path = invoker.input_jar_path
     _output_jar_path = invoker.output_jar_path
 
+    _proguard_preprocess =
+        defined(invoker.proguard_preprocess) && invoker.proguard_preprocess
+
     _jar_excluded_patterns = []
     if (defined(invoker.jar_excluded_patterns)) {
       _jar_excluded_patterns = invoker.jar_excluded_patterns
@@ -1002,24 +1004,15 @@ if (enable_java_templates) {
                               invoker.strip_resource_classes
     _filter_jar = _jar_excluded_patterns != [] || _strip_resource_classes
 
+    _enable_assert =
+        defined(invoker.supports_android) && invoker.supports_android &&
+        (is_java_debug || dcheck_always_on)
+    assert(_enable_assert || true)  # Mark used.
+
     if (_filter_jar) {
       _filter_target = "${target_name}__filter"
-      _output_jar_target = _filter_target
-    }
-    if (_proguard_preprocess) {
-      _proguard_target = "${target_name}__proguard_process"
-      _output_jar_target = _proguard_target
-    }
-    if (!_filter_jar && !_proguard_preprocess) {
-      _copy_target = "${target_name}__copy"
-      _output_jar_target = _copy_target
-    }
 
-    if (_filter_jar) {
-      _filtered_jar_path = _output_jar_path
-      if (_proguard_preprocess) {
-        _filtered_jar_path = "$target_out_dir/$target_name-filtered.jar"
-      }
+      _filter_jar_path = "$target_out_dir/$target_name-filtered.jar"
       action(_filter_target) {
         script = "//build/android/gyp/jar.py"
         forward_variables_from(invoker,
@@ -1032,13 +1025,13 @@ if (enable_java_templates) {
           _input_jar_path,
         ]
         outputs = [
-          _filtered_jar_path,
+          _filter_jar_path,
         ]
         args = [
           "--input-jar",
           rebase_path(_input_jar_path, root_build_dir),
           "--jar-path",
-          rebase_path(_filtered_jar_path, root_build_dir),
+          rebase_path(_filter_jar_path, root_build_dir),
           "--excluded-classes=$_jar_excluded_patterns",
         ]
         if (_strip_resource_classes) {
@@ -1048,31 +1041,34 @@ if (enable_java_templates) {
     }
 
     if (_proguard_preprocess) {
+      _output_jar_target = "${target_name}__proguard_process"
+      _proguard_output_jar = _output_jar_path
       _proguard_config_path = invoker.proguard_preprocess_config
-      proguard(_proguard_target) {
+      proguard(_output_jar_target) {
         if (_filter_jar) {
-          _proguard_input_jar = _filtered_jar_path
-          public_deps = [
+          _proguard_input_jar = _filter_jar_path
+          deps = [
             ":$_filter_target",
           ]
         } else {
           _proguard_input_jar = _input_jar_path
-          public_deps = []
+          deps = []
         }
         if (defined(invoker.deps)) {
-          deps = invoker.deps
+          deps += invoker.deps
         }
         if (defined(invoker.public_deps)) {
-          public_deps += invoker.public_deps
+          public_deps = invoker.public_deps
         }
         inputs = [
           _build_config,
           _proguard_config_path,
           _proguard_input_jar,
         ]
-        output_jar_path = _output_jar_path
+        output_jar_path = _proguard_output_jar
 
-        _rebased_input_paths = [ rebase_path(_input_jar_path, root_build_dir) ]
+        _rebased_input_paths =
+            [ rebase_path(_proguard_input_jar, root_build_dir) ]
         _rebased_proguard_configs =
             [ rebase_path(_proguard_config_path, root_build_dir) ]
         args = [
@@ -1081,15 +1077,57 @@ if (enable_java_templates) {
           "--classpath=@FileArg($_rebased_build_config:javac:classpath)",
         ]
       }
-    } else if (!_filter_jar) {
-      copy(_copy_target) {
-        forward_variables_from(invoker,
-                               [
-                                 "deps",
-                                 "public_deps",
-                               ])
+    } else if (_enable_assert) {
+      _output_jar_target = "${target_name}__assert"
+      _assert_output_jar = _output_jar_path
+      action(_output_jar_target) {
+        script = "$root_out_dir/bin/helper/java_assertion_enabler"
+        deps = [
+          "//build/android/java_assertion_enabler($default_toolchain)",
+        ]
+        if (_filter_jar) {
+          _assert_input_jar = _filter_jar_path
+          deps += [ ":$_filter_target" ]
+        } else {
+          _assert_input_jar = _input_jar_path
+        }
+        if (defined(invoker.deps)) {
+          deps += invoker.deps
+        }
+        if (defined(invoker.public_deps)) {
+          public_deps = invoker.public_deps
+        }
+        inputs = [
+          _assert_input_jar,
+        ]
+        outputs = [
+          _assert_output_jar,
+        ]
+        args = [
+          rebase_path(_assert_input_jar, root_build_dir),
+          rebase_path(_assert_output_jar, root_build_dir),
+        ]
+      }
+    } else {
+      _output_jar_target = "${target_name}__copy"
+      copy(_output_jar_target) {
+        if (_filter_jar) {
+          _copy_input_jar = _filter_jar_path
+          public_deps = [
+            ":$_filter_target",
+          ]
+        } else {
+          _copy_input_jar = _input_jar_path
+          public_deps = []
+        }
+        if (defined(invoker.deps)) {
+          deps = invoker.deps
+        }
+        if (defined(invoker.public_deps)) {
+          public_deps += invoker.public_deps
+        }
         sources = [
-          _input_jar_path,
+          _copy_input_jar,
         ]
         outputs = [
           _output_jar_path,
@@ -1785,6 +1823,7 @@ if (enable_java_templates) {
         visibility += [ ":$_dex_target_name" ]
       }
 
+      supports_android = _supports_android
       build_config = _build_config
       input_jar_path = invoker.jar_path
       output_jar_path = _jar_path
@@ -2076,6 +2115,7 @@ if (enable_java_templates) {
                                "proguard_preprocess",
                                "proguard_preprocess_config",
                              ])
+      supports_android = _supports_android
       build_config = _build_config
       input_jar_path = _javac_jar_path
       output_jar_path = _process_prebuilt_jar_path