Move retry and lhttp packages from client/internal to common/.

client/internal/retry/retry.go

Index: client/internal/retry/retry.go
diff --git a/client/internal/retry/retry.go b/client/internal/retry/retry.go
deleted file mode 100644
index 35582cb7bb542ca1f76be84146c48b3a9eeaa4e5..0000000000000000000000000000000000000000
--- a/client/internal/retry/retry.go
+++ /dev/null
@@ -1,66 +0,0 @@
-// Copyright 2015 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.
-
-package retry
-
-import (
-	"io"
-	"time"
-)
-
-// Default defines the default retry parameters that should be used throughout
-// the program. It is fine to update this variable on start up.
-var Default = &Config{
-	10,
-	100 * time.Millisecond,
-	500 * time.Millisecond,
-	5 * time.Second,
-}
-
-// Config defines the retry properties.
-type Config struct {
-	MaxTries            int           // Maximum number of retries.
-	SleepMax            time.Duration // Maximum duration of a single sleep.
-	SleepBase           time.Duration // Base sleep duration.
-	SleepMultiplicative time.Duration // Incremental sleep duration for each additional try.
-}
-
-// Do runs a Retriable, potentially retrying it multiple times.
-func (c *Config) Do(r Retriable) (err error) {
-	defer func() {
-		if err2 := r.Close(); err == nil {
-			err = err2
-		}
-	}()
-	for i := 0; i < c.MaxTries; i++ {
-		err = r.Do()
-		if _, ok := err.(Error); !ok {
-			return err
-		}
-		if i != c.MaxTries-1 {
-			s := c.SleepBase + time.Duration(i)*c.SleepMultiplicative
-			if s > c.SleepMax {
-				s = c.SleepMax
-			}
-			time.Sleep(s)
-		}
-	}
-	return
-}
-
-// Error is an error that can be retried.
-type Error struct {
-	Err error
-}
-
-func (e Error) Error() string {
-	return e.Err.Error()
-}
-
-// Retriable is a task that can be retried. It is important that Do be
-// idempotent.
-type Retriable interface {
-	io.Closer
-	Do() error
-}