[Downloads] Rework how hashes are calculated for download files.

content/public/browser/download_interrupt_reason_values.h

 // Copyright (c) 2011 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.
 
 // Note that the embedder is welcome to persist these values across
 // invocations of the browser, and possibly across browser versions.
 // Thus individual errors may be deprecated and new errors added, but
 // the values of particular errors should not be changed.
 
 // File errors.
@@ skipping 33 matching lines @@
 INTERRUPT_REASON(FILE_BLOCKED, 11)
 
 // An attempt to check the safety of the download failed due to unexpected
 // reasons. See http://crbug.com/153212.
 INTERRUPT_REASON(FILE_SECURITY_CHECK_FAILED, 12)
 
 // An attempt was made to seek past the end of a file in opening
 // a file (as part of resuming a previously interrupted download).
 INTERRUPT_REASON(FILE_TOO_SHORT, 13)
 
+// The partial file didn't match the expected hash.
+INTERRUPT_REASON(FILE_HASH_MISMATCH, 14)
+
 // Network errors.
 
 // Generic network failure.
 // "Network Error".
 INTERRUPT_REASON(NETWORK_FAILED, 20)
 
 // The network operation timed out.
 // "Operation Timed Out".
 INTERRUPT_REASON(NETWORK_TIMEOUT, 21)
 
@@ skipping 55 matching lines @@
 // The user shut down the browser.
 // Internal use only:  resume pending downloads if possible.
 INTERRUPT_REASON(USER_SHUTDOWN, 41)
 
 
 // Crash.
 
 // The browser crashed.
 // Internal use only:  resume pending downloads if possible.
 INTERRUPT_REASON(CRASH, 50)