Make a ResourceThrottle for extensions on top of net::URLRequestThrottlerManager.

net::URLRequestThrottlerManager is used for throttling extensions originated
requests. We would like to move it out of net/ and place it in a more appropriate
directory. Since content::ResourceThrottle is the standard way to throttle
requests, this CL makes URLRequestThrottlerManager into a extensions
ResourceThrottle and place it in extensions/browser/. Followup CLs will clean up
URLRequestThrottlerManager usage from net/.

BUG=484241

Review URL: https://codereview.chromium.org/1171983003

Cr-Commit-Position: refs/heads/master@{#334457}

1 files changed, 52 insertions, 0 deletions

diff --git a/extensions/browser/extension_request_limiting_throttle.h b/extensions/browser/extension_request_limiting_throttle.h
new file mode 100644
index 0000000..bd9dd4c
--- /dev/null
+++ b/extensions/browser/extension_request_limiting_throttle.h
@@ -0,0 +1,52 @@
+// 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.
+
+#ifndef EXTENSIONS_BROWSER_EXTENSION_REQUEST_LIMITING_THROTTLE_H_
+#define EXTENSIONS_BROWSER_EXTENSION_REQUEST_LIMITING_THROTTLE_H_
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "content/public/browser/resource_throttle.h"
+
+namespace net {
+struct RedirectInfo;
+class URLRequest;
+}
+
+namespace extensions {
+
+class ExtensionThrottleEntryInterface;
+class ExtensionThrottleManager;
+
+// This class monitors requests issued by extensions and throttles the request
+// if there are too many requests made within a short time to urls with the same
+// scheme, host, port and path. For the exact criteria for throttling, please
+// also see extension_throttle_manager.cc.
+class ExtensionRequestLimitingThrottle : public content::ResourceThrottle {
+ public:
+  ExtensionRequestLimitingThrottle(const net::URLRequest* request,
+                                   ExtensionThrottleManager* manager);
+  ~ExtensionRequestLimitingThrottle() override;
+
+  // content::ResourceThrottle implementation (called on IO thread):
+  void WillStartRequest(bool* defer) override;
+  void WillRedirectRequest(const net::RedirectInfo& redirect_info,
+                           bool* defer) override;
+  void WillProcessResponse(bool* defer) override;
+
+  const char* GetNameForLogging() const override;
+
+ private:
+  const net::URLRequest* request_;
+  ExtensionThrottleManager* manager_;
+
+  // This is used to supervise traffic and enforce exponential back-off.
+  scoped_refptr<ExtensionThrottleEntryInterface> throttling_entry_;
+
+  DISALLOW_COPY_AND_ASSIGN(ExtensionRequestLimitingThrottle);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_EXTENSION_REQUEST_LIMITING_THROTTLE_H_