Add support to URLRequest for deferring redirects.

I chose to add an out parameter to OnReceivedRedirect because it allows for the
default behavior to remain the same.

I considered adding a ContinueAfterRedirect method that all OnReceivedRedirect
implementations would need to call, but this caused one annoying problem:  In
the case of a ChromePlugin, it is possible for the URLRequest to get deleted
inside the handler for the redirect.  This would make it hard to subsequently
call a method on the URLRequest since I would need to have a way to determine
if the URLRequest had been deleted.

TEST=covered by unit tests
BUG=16413,6442
R=eroman,wtc

Review URL: http://codereview.chromium.org/155897

git-svn-id: http://src.chromium.org/svn/trunk/src/net/tools/testserver@21417 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
diff --git a/testserver.py b/testserver.py
index 06bcfad..14ae182 100644
--- a/testserver.py
+++ b/testserver.py
@@ -570,6 +570,10 @@
     if not self.path.startswith(prefix):
       return False
 
+    # Consume a request body if present.
+    if self.command == 'POST':
+      self.rfile.read(int(self.headers.getheader('content-length')))
+
     file = self.path[len(prefix):]
     entries = file.split('/');
     path = os.path.join(self.server.data_dir, *entries)