Add DataReductionProxy IPC to determine if the Data Reduction Proxy was used.

components/data_reduction_proxy/content/browser/data_reduction_proxy_message_filter.cc

Index: components/data_reduction_proxy/content/browser/data_reduction_proxy_message_filter.cc
diff --git a/components/data_reduction_proxy/content/browser/data_reduction_proxy_message_filter.cc b/components/data_reduction_proxy/content/browser/data_reduction_proxy_message_filter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e01c4998d715aba61b5cd09f2f383ca892531dc8
--- /dev/null
+++ b/components/data_reduction_proxy/content/browser/data_reduction_proxy_message_filter.cc
@@ -0,0 +1,54 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/data_reduction_proxy/content/browser/data_reduction_proxy_message_filter.h"
+
+#include "components/data_reduction_proxy/content/common/data_reduction_proxy_messages.h"
+#include "components/data_reduction_proxy/core/browser/data_reduction_proxy_config.h"
+#include "components/data_reduction_proxy/core/browser/data_reduction_proxy_settings.h"
+#include "content/public/browser/browser_thread.h"
+#include "ipc/ipc_message_macros.h"
+#include "net/base/host_port_pair.h"
+
+namespace data_reduction_proxy {
+
+DataReductionProxyMessageFilter::DataReductionProxyMessageFilter(
+    DataReductionProxySettings* settings)
+    : BrowserMessageFilter(DataReductionProxyStart),
+      config_(nullptr) {
+  DCHECK(settings);
+  config_ = settings->Config();
+}
+
+DataReductionProxyMessageFilter::~DataReductionProxyMessageFilter() {
+}
+
+bool DataReductionProxyMessageFilter::OnMessageReceived(
+    const IPC::Message& message) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP(DataReductionProxyMessageFilter, message)
+    IPC_MESSAGE_HANDLER(DataReductionProxyViewHostMsg_IsDataReductionProxy,
+                        OnIsDataReductionProxy)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+  return handled;
+}
+
+void DataReductionProxyMessageFilter::OverrideThreadForMessage(
+    const IPC::Message& message, content::BrowserThread::ID* thread) {
+  if (message.type() ==
+          DataReductionProxyViewHostMsg_IsDataReductionProxy::ID) {
+      *thread = content::BrowserThread::IO;
+  }
+}
+
+void DataReductionProxyMessageFilter::OnIsDataReductionProxy(
+    const net::HostPortPair& proxy_server, bool* response) {
+  if (config_)
+    *response = config_->IsDataReductionProxy(proxy_server, nullptr);
+  else
+    *response = false;
+}
+
+}  // namespace data_reduction_proxy