Remove som GYP annotations, remove unused manifest.

base/android/jni_generator/BUILD.gn

Index: base/android/jni_generator/BUILD.gn
diff --git a/base/android/jni_generator/BUILD.gn b/base/android/jni_generator/BUILD.gn
index 1d9890224974c87106ce1b4939ed3270e8872306..1741e51ea531ad57ba1ccfe3a893f2e40c6f1161 100644
--- a/base/android/jni_generator/BUILD.gn
+++ b/base/android/jni_generator/BUILD.gn
@@ -5,7 +5,6 @@
 import("//build/config/android/rules.gni")
 import("//testing/test.gni")
 
-# GYP: //base/android/jni_generator/jni_generator.gyp:jni_generator_py_tests
 action("jni_generator_py_tests") {
   _stamp = "$target_gen_dir/jni_generator_py_tests.stamp"
   inputs = [
@@ -24,7 +23,6 @@ action("jni_generator_py_tests") {
   ]
 }
 
-# GYP: //base/android/jni_generator/jni_generator.gyp:jni_sample_header
 generate_jni("jni_sample_header") {
   sources = [
     "java/src/org/chromium/example/jni_generator/SampleForTests.java",
@@ -32,7 +30,6 @@ generate_jni("jni_sample_header") {
   jni_package = "example"
 }
 
-# GYP: //base/android/jni_generator/jni_generator.gyp:jni_sample_java
 android_library("jni_sample_java") {
   java_files =
       [ "java/src/org/chromium/example/jni_generator/SampleForTests.java" ]
@@ -43,7 +40,6 @@ android_library("jni_sample_java") {
 
 # This executable doesn't actually run, but at least serves to test that
 # generated bindings compile properly.
-# GYP: //base/android/jni_generator/jni_generator.gyp:jni_generator_tests
 executable("jni_generator_tests") {
   deps = [
     ":jni_generator_py_tests",