Randomize proxy timeout on Android over a range.

net/proxy/proxy_list.cc

Index: net/proxy/proxy_list.cc
diff --git a/net/proxy/proxy_list.cc b/net/proxy/proxy_list.cc
index a3ab02c392a638643fd0b9a06a72cbb77a5bcf69..5330ff48682500909233683f62c71bf3c542dc96 100644
--- a/net/proxy/proxy_list.cc
+++ b/net/proxy/proxy_list.cc
@@ -6,6 +6,7 @@
 
 #include "base/callback.h"
 #include "base/logging.h"
+#include "base/rand_util.h"
 #include "base/strings/string_tokenizer.h"
 #include "base/time.h"
 #include "base/values.h"
@@ -193,9 +194,11 @@ bool ProxyList::Fallback(ProxyRetryInfoMap* proxy_retry_info,
 
 void ProxyList::UpdateRetryInfoOnFallback(
     ProxyRetryInfoMap* proxy_retry_info, const BoundNetLog& net_log) const {
-  // Number of minutes to wait before retrying a bad proxy server.
+  // Time to wait before retrying a bad proxy server.
 #if defined(OS_ANDROID)
-  const TimeDelta kProxyRetryDelay = TimeDelta::FromMinutes(1);
+  // Randomize the timeout over a range from one to five minutes.
+  const TimeDelta kProxyRetryDelay =
+      TimeDelta::FromMilliseconds(base::RandInt(1 * 60 * 1000, 5 * 60 * 1000));

[mmenke, 2013/05/08 16:50:08]

const Blah kBlah is generally only used for values that are always constant.  I
don't think I've ever seen it used for a randomized value, so this seems a
little weird.

I'm open to suggestions of prettier ways to do this.  If not, I'll think about
it and get back to you later (Probably today, possibly tomorrow).

[cbentzel, 2013/05/08 16:57:18]

proxy_retry_delay?

I don't think the const buys us much here.

[mmenke, 2013/05/08 16:58:58]

The nice thing about the const is that it draws attention to "Thar be hard-coded
constants here!"

I'm fine with that solution, though.

[bengr, 2013/05/08 17:23:11]

Yeah, I thought about three ways of writing this: (1) declare some constants,
which seemed liked overkill, considering the retry delay on line 203 isn't
declared that way; (2) use TimeDelta as a way of calling out that this is a
constant:
const TimeDelta kProxyRetryDelay =
    TimeDelta::FromMilliseconds(base::RandInt(
        TimeDelta::FromMinutes(1).InMilliseconds(),
        TimeDelta::FromMinutes(5).InMilliseconds()));
(3) what's in this CL.

 #else
   const TimeDelta kProxyRetryDelay = TimeDelta::FromMinutes(5);
 #endif