Backoff: Respect maximum delay in face of float overflow

net/base/backoff_entry_unittest.cc

Index: net/base/backoff_entry_unittest.cc
diff --git a/net/base/backoff_entry_unittest.cc b/net/base/backoff_entry_unittest.cc
index 9a9f4cfca0a232024182784f87d5d4a9b19f579a..c2bfc943d80b153a7be56690d1496d0839f5f05e 100644
--- a/net/base/backoff_entry_unittest.cc
+++ b/net/base/backoff_entry_unittest.cc
@@ -293,4 +293,19 @@ TEST(BackoffEntryTest, RetainCustomHorizonWhenInitialErrorsIgnored) {
   EXPECT_EQ(custom_horizon, custom.GetReleaseTime());
 }
 
+TEST(BackoffEntryTest, OverflowProtection) {
+  TestBackoffEntry custom(&base_policy);
+
+  // Trigger enough failures such that more than 11 bits of exponent are used
+  // to represent the exponential backoff intermediate values.

[cbentzel, 2014/06/14 15:16:07]

Could you use a different policy for this test with a larger
multiplication_factor to reduce the number of cycles needed to reach overflow?

[Nicolas Zea, 2014/06/16 20:27:25]

Done.

+  for (size_t i = 0; i < (1 << 11); ++i) {
+     custom.set_now(custom.ImplGetTimeNow() + custom.GetTimeUntilRelease());
+     custom.InformOfRequest(false);
+     EXPECT_TRUE(custom.ShouldRejectRequest());
+  }
+
+  // Max delay should still be respected.
+  EXPECT_EQ(20000, custom.GetTimeUntilRelease().InMilliseconds());
+}
+
 }  // namespace