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, 76 insertions, 0 deletions

diff --git a/extensions/browser/extension_throttle_entry_interface.h b/extensions/browser/extension_throttle_entry_interface.h
new file mode 100644
index 0000000..99989b8
--- /dev/null
+++ b/extensions/browser/extension_throttle_entry_interface.h
@@ -0,0 +1,76 @@
+// Copyright (c) 2012 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_THROTTLE_ENTRY_INTERFACE_H_
+#define EXTENSIONS_BROWSER_EXTENSION_THROTTLE_ENTRY_INTERFACE_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "base/time/time.h"
+#include "net/base/net_export.h"
+
+namespace net {
+class URLRequest;
+}  // namespace net
+
+namespace extensions {
+
+// Interface provided on entries of the URL request throttler manager.
+class ExtensionThrottleEntryInterface
+    : public base::RefCountedThreadSafe<ExtensionThrottleEntryInterface> {
+ public:
+  ExtensionThrottleEntryInterface() {}
+
+  // Returns true when we have encountered server errors and are doing
+  // exponential back-off, unless the request has load flags that mean
+  // it is likely to be user-initiated, or the NetworkDelegate returns
+  // false for |CanThrottleRequest(request)|.
+  //
+  // URLRequestHttpJob checks this method prior to every request; it
+  // cancels requests if this method returns true.
+  virtual bool ShouldRejectRequest(const net::URLRequest& request) const = 0;
+
+  // Calculates a recommended sending time for the next request and reserves it.
+  // The sending time is not earlier than the current exponential back-off
+  // release time or |earliest_time|. Moreover, the previous results of
+  // the method are taken into account, in order to make sure they are spread
+  // properly over time.
+  // Returns the recommended delay before sending the next request, in
+  // milliseconds. The return value is always positive or 0.
+  // Although it is not mandatory, respecting the value returned by this method
+  // is helpful to avoid traffic overload.
+  virtual int64 ReserveSendingTimeForNextRequest(
+      const base::TimeTicks& earliest_time) = 0;
+
+  // Returns the time after which requests are allowed.
+  virtual base::TimeTicks GetExponentialBackoffReleaseTime() const = 0;
+
+  // This method needs to be called each time a response is received.
+  virtual void UpdateWithResponse(int status_code) = 0;
+
+  // Lets higher-level modules, that know how to parse particular response
+  // bodies, notify of receiving malformed content for the given URL. This will
+  // be handled by the throttler as if an HTTP 503 response had been received to
+  // the request, i.e. it will count as a failure, unless the HTTP response code
+  // indicated is already one of those that will be counted as an error.
+  virtual void ReceivedContentWasMalformed(int response_code) = 0;
+
+  // Get the URL ID associated with his entry. Should only be used for debugging
+  // purpose.
+  virtual const std::string& GetURLIdForDebugging() const = 0;
+
+ protected:
+  friend class base::RefCountedThreadSafe<ExtensionThrottleEntryInterface>;
+  virtual ~ExtensionThrottleEntryInterface() {}
+
+ private:
+  friend class base::RefCounted<ExtensionThrottleEntryInterface>;
+  DISALLOW_COPY_AND_ASSIGN(ExtensionThrottleEntryInterface);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_EXTENSION_THROTTLE_ENTRY_INTERFACE_H_