Add an IPC method for Blink to call RapporService::RecordSample()

components/rappor/BUILD.gn

Index: components/rappor/BUILD.gn
diff --git a/components/rappor/BUILD.gn b/components/rappor/BUILD.gn
index 8bad34763dfdb8954a7c35a0060c0ebc48cc2953..42e28defa47f9052b253c8e18c94bfc46b53e55c 100644
--- a/components/rappor/BUILD.gn
+++ b/components/rappor/BUILD.gn
@@ -12,6 +12,10 @@ static_library("rappor") {
     "log_uploader.cc",
     "log_uploader.h",
     "log_uploader_interface.h",
+    "rappor_message_filter.cc",
+    "rappor_message_filter.h",
+    "rappor_messages.cc",
+    "rappor_messages.h",
     "rappor_metric.cc",
     "rappor_metric.h",
     "rappor_parameters.cc",