Implement exponential back-off mechanism and enforce it at the URLRequestHttpJob level.

chrome/service/cloud_print/cloud_print_consts.h

Index: chrome/service/cloud_print/cloud_print_consts.h
===================================================================
--- chrome/service/cloud_print/cloud_print_consts.h	(revision 66188)
+++ chrome/service/cloud_print/cloud_print_consts.h	(working copy)
@@ -36,14 +36,12 @@
 extern const char kSyncGaiaServiceId[];
 extern const char kCloudPrintPushNotificationsSource[];
 extern const char kChromeCloudPrintProxyHeader[];
-extern const char kCloudPrintAPIRetryPolicy[];
-extern const char kJobDataRetryPolicy[];
 extern const char kCloudPrintUserAgent[];
 
 // Max retry count for job data fetch requests.
 const int kJobDataMaxRetryCount = 5;
-// Look at CloudPrintProxyBackend::Core::CreateDefaultRetryPolicy for default
-// values of the request retry policy.
+// Max retry count (infinity) for API fetch requests.
+const int kCloudPrintAPIMaxRetryCount = -1;
 
 // When we don't have XMPP notifications available, we resort to polling for
 // print jobs. We choose a random interval in seconds between these 2 values.