Remaining changes needed to get QPS test working on old compilers.
This change contains a lot of ugly changes, such as changing
std::vector to allocation by new, etc.
diff --git a/test/cpp/qps/client.h b/test/cpp/qps/client.h
index c7f206d..c7513ed 100644
--- a/test/cpp/qps/client.h
+++ b/test/cpp/qps/client.h
@@ -69,10 +69,10 @@
 class Client {
  public:
   explicit Client(const ClientConfig& config)
-      : timer_(new Timer), interarrival_timer_() {
+    : channels_(config.client_channels()), timer_(new Timer), interarrival_timer_() {
     for (int i = 0; i < config.client_channels(); i++) {
-      channels_.emplace_back(
-          config.server_targets(i % config.server_targets_size()), config);
+      channels_[i].init(config.server_targets(i % config.server_targets_size()),
+			config);
     }
     request_.set_response_type(grpc::testing::PayloadType::COMPRESSABLE);
     request_.set_response_size(config.payload_size());
@@ -81,7 +81,7 @@
 
   ClientStats Mark() {
     Histogram latencies;
-    std::vector<Histogram> to_merge(threads_.size());
+    Histogram to_merge[threads_.size()]; // avoid std::vector for old compilers
     for (size_t i = 0; i < threads_.size(); i++) {
       threads_[i]->BeginSwap(&to_merge[i]);
     }
@@ -108,12 +108,16 @@
 
   class ClientChannelInfo {
    public:
-    ClientChannelInfo(const grpc::string& target, const ClientConfig& config)
-        : channel_(CreateTestChannel(target, config.enable_ssl())),
-          stub_(TestService::NewStub(channel_)) {}
+    ClientChannelInfo() {}
+    ClientChannelInfo(const ClientChannelInfo& i): channel_(), stub_() {
+      GPR_ASSERT(!i.channel_ && !i.stub_);
+    }
+    void init(const grpc::string& target, const ClientConfig& config) {
+      channel_ = CreateTestChannel(target, config.enable_ssl());
+      stub_ = TestService::NewStub(channel_);
+    }
     ChannelInterface* get_channel() { return channel_.get(); }
     TestService::Stub* get_stub() { return stub_.get(); }
-
    private:
     std::shared_ptr<ChannelInterface> channel_;
     std::unique_ptr<TestService::Stub> stub_;