Add experimental code behind a flag for Content Size Policy

content/browser/loader/content_size_resource_handler.cc

Index: content/browser/loader/content_size_resource_handler.cc
diff --git a/content/browser/loader/content_size_resource_handler.cc b/content/browser/loader/content_size_resource_handler.cc
new file mode 100644
index 0000000000000000000000000000000000000000..724f7e25221dab1c704c9214bcc2f361653c71f3
--- /dev/null
+++ b/content/browser/loader/content_size_resource_handler.cc
@@ -0,0 +1,41 @@
+// 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 "content/browser/loader/content_size_resource_handler.h"
+
+#include "content/browser/loader/content_size_resource_handler_manager.h"
+#include "net/url_request/url_request.h"
+
+namespace content {
+
+ContentSizeResourceHandler::ContentSizeResourceHandler(
+    std::unique_ptr<ResourceHandler> next_handler,
+    net::URLRequest* request,
+    ContentSizeResourceHandlerManager* manager)
+    : LayeredResourceHandler(request, std::move(next_handler)),
+      manager_(manager) {}
+
+ContentSizeResourceHandler::~ContentSizeResourceHandler() {}
+
+bool ContentSizeResourceHandler::OnWillStart(const GURL& url, bool* defer) {
+  if (manager_->ShouldCancelRequest(GetRequestInfo(), 0))
+    return false;
+  return next_handler_->OnWillStart(url, defer);
+}
+
+bool ContentSizeResourceHandler::OnReadCompleted(int bytes_read, bool* defer) {
+  if (manager_->ShouldCancelRequest(GetRequestInfo(), bytes_read))
+    return false;
+  return next_handler_->OnReadCompleted(bytes_read, defer);
+}
+
+void ContentSizeResourceHandler::OnResponseCompleted(
+    const net::URLRequestStatus& status,
+    const std::string& security_info,
+    bool* defer) {
+  manager_->NotifyUIThreadReadUpdates();
+  next_handler_->OnResponseCompleted(status, security_info, defer);
+}
+
+}  // namespace content