gn2bp: add support for genrule_header_libs

Test: //base:base
Change-Id: I0859e0a6da11afdc744fe863e29921297c7f8fe0
diff --git a/tools/gn2bp/gen_android_bp b/tools/gn2bp/gen_android_bp
index 4505b7a..d01c5bd 100755
--- a/tools/gn2bp/gen_android_bp
+++ b/tools/gn2bp/gen_android_bp
@@ -355,6 +355,7 @@
     self.genrule_headers = set()
     self.genrule_srcs = set()
     self.genrule_shared_libs = set()
+    self.genrule_header_libs = set()
     self.version_script = None
     self.test_suites = set()
     self.test_config = None
@@ -897,6 +898,7 @@
       module.generated_headers.update(dep_module.genrule_headers)
       module.srcs.update(dep_module.genrule_srcs)
       module.shared_libs.update(dep_module.genrule_shared_libs)
+      module.header_libs.update(dep_module.genrule_header_libs)
     elif dep_module.type == 'cc_binary':
       continue  # Ignore executables deps (used by cmdline integration tests).
     else: