Port cronet build rules to GN part 1

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 3216b4c2cd365e63d05adbb27f67db475665e04f..4a28ed4172c8b7e62ca9b58e66650cdb67b020b3 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -314,6 +314,16 @@ group("both_gn_and_gyp") {
       "//url:url_unittests",
     ]
 
+    if (!is_component_build) {
+      deps += [
+        "//components/cronet/android:cronet_sample_apk",
+        "//components/cronet/android:cronet_sample_test_apk",
+        "//components/cronet/android:cronet_test_apk",
+        "//components/cronet/android:cronet_test_instrumentation_apk",
+        "//components/cronet/android:cronet_unittests",
+      ]
+    }
+
     if (!is_chromecast) {
       deps += [
         "//android_webview",