feat: add C++ targets for DialogFlow

PiperOrigin-RevId: 351615861

.kokoro/setup.sh

@@ -2,6 +2,21 @@
 
 set -e
 
+#
+# Update GCC
+#
+update_gcc() {
+  sudo add-apt-repository ppa:ubuntu-toolchain-r/test -y
+  sudo apt-get update
+  sudo apt-get install -y gcc-6 g++-6
+}
+
+time {
+  update_gcc || sleep 10 || update_gcc || sleep 20 || update_gcc
+}
+export CXX=g++-6
+export CC=gcc-6
+
 #
 # Install bazelisk
 #

google/cloud/dialogflow/v2/BUILD.bazel

@@ -362,4 +362,20 @@ csharp_gapic_assembly_pkg(
 ##############################################################################
 # C++
 ##############################################################################
-# Put your C++ rules here
+load(
+    "@com_google_googleapis_imports//:imports.bzl",
+    "cc_grpc_library",
+    "cc_proto_library",
+)
+
+cc_proto_library(
+    name = "dialogflow_cc_proto",
+    deps = [":dialogflow_proto"],
+)
+
+cc_grpc_library(
+    name = "dialogflow_cc_grpc",
+    srcs = [":dialogflow_proto"],
+    grpc_only = True,
+    deps = [":dialogflow_cc_proto"],
+)