Migrate components/data_reduction_proxy to Mojo interfaces.

components/data_reduction_proxy/content/browser/data_reduction_proxy_host_impl.cc

+// Copyright 2016 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_host_impl.h"
+
+#include "components/data_reduction_proxy/core/browser/data_reduction_proxy_config.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/render_process_host.h"
+#include "net/base/host_port_pair.h"
+
+namespace data_reduction_proxy {
+
+DataReductionProxyHostImpl::DataReductionProxyHostImpl(
+    DataReductionProxyConfig* config,
+    content::RenderProcessHost* host)
+    : config_(config) {
+  // Unit tests may pass nullptr as |host|.
+  if (host)
+    host->AddObserver(this);
+}
+
+DataReductionProxyHostImpl::~DataReductionProxyHostImpl() {}
+
+void DataReductionProxyHostImpl::BindRequest(
+    mojom::DataReductionProxyHostRequest request) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+  bindings_.AddBinding(this, std::move(request));
+}
+
+void DataReductionProxyHostImpl::IsDataReductionProxy(
+    const net::HostPortPair& proxy_server,
+    const IsDataReductionProxyCallback& callback) {
+  if (!config_) {
+    callback.Run(false);
+    return;
+  }
+
+  callback.Run(config_->IsDataReductionProxy(proxy_server, nullptr));
+}
+
+void DataReductionProxyHostImpl::RenderProcessHostDestroyed(

[Anand Mistry (off Chromium), 2016/06/30 12:51:45]

RenderProcessHosts can be reused. And every time, a new set of Mojo services is
registered. This means you'll end up with zombie DataReductionProxyHostImpls
until the RPH is finally destroyed. I think you want RenderProcessHostExited
instead which runs when the renderer process exits.

[leonhsl(Using Gerrit), 2016/07/01 02:25:57]

Oh, yeah, I see now.. Thanks a lot for pointing out this! I really learned a lot
from this CL! Done.

+    content::RenderProcessHost* host) {
+  content::BrowserThread::DeleteSoon(content::BrowserThread::IO, FROM_HERE,
+                                     this);
+}
+
+}  // namespace data_reduction_proxy