Remove GYP annotations from third_party GN files.

third_party/cacheinvalidation/BUILD.gn

Index: third_party/cacheinvalidation/BUILD.gn
diff --git a/third_party/cacheinvalidation/BUILD.gn b/third_party/cacheinvalidation/BUILD.gn
index 70be8c68a0b64d9782fd74f552d049ffabe235ab..f8f6d60352931fe3e78cf8246f89490276695a8a 100644
--- a/third_party/cacheinvalidation/BUILD.gn
+++ b/third_party/cacheinvalidation/BUILD.gn
@@ -117,7 +117,6 @@ test("cacheinvalidation_unittests") {
 if (is_android) {
   import("//build/config/android/rules.gni")
 
-  # GYP: //third_party/cacheinvalidation/cacheinvalidation.gyp:cacheinvalidation_proto_java
   proto_java_library("cacheinvalidation_proto_java") {
     proto_path = "src/proto"
     sources = [
@@ -132,7 +131,6 @@ if (is_android) {
     ]
   }
 
-  # GYP: //third_party/cacheinvalidation/cacheinvalidation.gyp:cacheinvalidation_javalib
   android_library("cacheinvalidation_javalib") {
     chromium_code = false
     emma_never_instrument = true