Implement chrome://view-http-cache with network service.

content/network/cache_url_loader.cc

Index: content/network/cache_url_loader.cc
diff --git a/content/network/cache_url_loader.cc b/content/network/cache_url_loader.cc
new file mode 100644
index 0000000000000000000000000000000000000000..d678a69e7c67da7a54ae1a747f6a55f6371ed236
--- /dev/null
+++ b/content/network/cache_url_loader.cc
@@ -0,0 +1,93 @@
+// Copyright 2017 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 "content/network/cache_url_loader.h"
+
+#include "base/bind.h"
+#include "base/macros.h"
+#include "base/strings/string_util.h"
+#include "content/public/common/url_constants.h"
+#include "mojo/common/data_pipe_utils.h"
+#include "net/url_request/view_cache_helper.h"
+
+namespace content {
+
+namespace {
+
+class CacheURLLoader {
+ public:
+  CacheURLLoader(const ResourceRequest& request,
+                 net::URLRequestContext* request_context,
+                 mojom::URLLoaderClientPtr client)
+      : client_(std::move(client)) {
+    scoped_refptr<net::HttpResponseHeaders> headers(
+        new net::HttpResponseHeaders("HTTP/1.1 200 OK"));
+    ResourceResponseHead resource_response;
+    resource_response.headers = headers;
+    resource_response.mime_type = "text/html";
+    client_->OnReceiveResponse(resource_response, base::nullopt, nullptr);
+
+    std::string cache_key =
+        request.url.spec().substr(strlen(kChromeUINetworkViewCacheURL));
+
+    int rv;
+    if (cache_key.empty()) {
+      rv = cache_helper_.GetContentsHTML(
+          request_context, kChromeUINetworkViewCacheURL, &data_,
+          base::Bind(&CacheURLLoader::DataAvailable, base::Unretained(this)));
+    } else {
+      rv = cache_helper_.GetEntryInfoHTML(
+          cache_key, request_context, &data_,
+          base::Bind(&CacheURLLoader::DataAvailable, base::Unretained(this)));
+    }
+
+    if (rv != net::ERR_IO_PENDING)
+      DataAvailable(rv);

[mmenke, 2017/05/10 19:01:53]

Is it safe to call delete this in a constructor?

[jam, 2017/05/10 22:02:53]

It is for now, but you're right this is bordering on undocumented behavior so
I've done it in a posttask.

+  }
+
+ private:
+  ~CacheURLLoader() {}
+
+  void DataAvailable(int result) {
+    DCHECK_EQ(net::OK, result);
+    MojoCreateDataPipeOptions options;
+    options.struct_size = sizeof(MojoCreateDataPipeOptions);
+    options.flags = MOJO_CREATE_DATA_PIPE_OPTIONS_FLAG_NONE;
+    options.element_num_bytes = 1;
+    options.capacity_num_bytes = data_.size();
+    mojo::DataPipe data_pipe(options);
+
+    DCHECK(data_pipe.producer_handle.is_valid());
+    DCHECK(data_pipe.consumer_handle.is_valid());
+
+    CHECK(
+        mojo::common::BlockingCopyFromString(data_, data_pipe.producer_handle));
+
+    client_->OnStartLoadingResponseBody(std::move(data_pipe.consumer_handle));
+
+    ResourceRequestCompletionStatus request_complete_data;
+    request_complete_data.error_code = net::OK;
+    request_complete_data.exists_in_cache = false;
+    request_complete_data.completion_time = base::TimeTicks::Now();
+    request_complete_data.encoded_data_length = data_.size();
+    request_complete_data.encoded_body_length = data_.size();
+    client_->OnComplete(request_complete_data);
+    delete this;
+  }
+
+  std::string data_;
+  mojom::URLLoaderClientPtr client_;
+  net::ViewCacheHelper cache_helper_;
+
+  DISALLOW_COPY_AND_ASSIGN(CacheURLLoader);
+};
+}
+
+void StartCacheURLLoader(const ResourceRequest& request,
+                         net::URLRequestContext* request_context,
+                         mojom::URLLoaderClientPtr client) {
+  new CacheURLLoader(request, request_context, std::move(client));

[mmenke, 2017/05/10 19:01:53]

Maybe a comment that the CacheURLLoader owns itself, and will delete itself when
done?

[jam, 2017/05/10 22:02:53]

I think this is obvious from looking at the small file.

+}
+
+}  // namespace content