Support enabling/disabling the URL request throttler via the about:net-internals page:

- Add a new tab to the about:net-internals page.
- Add a preference item to persist user's choice.
- Remove the command line switch --disable-enforced-throttling.
- Make throttling feature off by default for now.

This is 95% based on yzshen@chromium.org's patch
http://codereview.chromium.org/6286001/ which was never landed. The
changes that have been made from that patch are mostly cosmetic, apart
from updating it to match the codebase (the patch was prepared ~2
months ago) and responding to eroman@'s initial round of code review
comments.

BUG=66062
TEST=Make sure the checkbox on about:net-internals > HTTP Throttling is checked.
(1) Type in the addresss bar a URL which is expected to return 5XX.
(2) Keep clicking the "reload" button.
(3) After a few clicks, Chrome displays an error page explaining why a net::ERR_TEMPORARILY_THROTTLED error occurs.
Make sure the checkbox on about:net-internals > HTTP Throttling is unchecked.
Following step (1) and (2) described above won't result in a net::ERR_TEMPORARILY_THROTTLED error page.

Review URL: http://codereview.chromium.org/6677085

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@79455 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 10 insertions, 4 deletions

diff --git a/net/url_request/url_request_throttler_manager.h b/net/url_request/url_request_throttler_manager.h
index c48e917..d65b20f 100644
--- a/net/url_request/url_request_throttler_manager.h
+++ b/net/url_request/url_request_throttler_manager.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -53,9 +53,15 @@ class URLRequestThrottlerManager : public base::NonThreadSafe {
   // It is only used by unit tests.
   void EraseEntryForTests(const GURL& url);
 
-  void InitializeOptions(bool enforce_throttling);
+  // Turns threading model verification on or off.  Any code that correctly
+  // uses the network stack should preferably call this function to enable
+  // verification of correct adherence to the network stack threading model.
+  void set_enable_thread_checks(bool enable);
+  bool enable_thread_checks() const;
 
-  bool enforce_throttling() const { return enforce_throttling_; }
+  // Whether throttling is enabled or not.
+  void set_enforce_throttling(bool enforce);
+  bool enforce_throttling();
 
  protected:
   URLRequestThrottlerManager();
@@ -113,7 +119,7 @@ class URLRequestThrottlerManager : public base::NonThreadSafe {
   //
   // TODO(joi): See if we can fix the offending unit tests and remove this
   // workaround.
-  bool being_tested_;
+  bool enable_thread_checks_;
 
   DISALLOW_COPY_AND_ASSIGN(URLRequestThrottlerManager);
 };