Do not try to decrypt password protected RARs

R=jialiul

Bug: 855202
Change-Id: I100381590c3d87b5aeae8711abe2a38c8a28d8a5
Reviewed-on: https://chromium-review.googlesource.com/1110949
Commit-Queue: Jialiu Lin <jialiul@chromium.org>
Reviewed-by: Jialiu Lin <jialiul@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570549}

third_party/unrar/src/arcread.cpp

@@ -142,7 +142,8 @@ size_t Archive::ReadHeader15()
 
   if (Decrypt)
   {
-#ifdef RAR_NOCRYPT // For rarext.dll and unrar_nocrypt.dll.
+#if defined(RAR_NOCRYPT) || \
+    defined(CHROMIUM_UNRAR)  // For rarext.dll and unrar_nocrypt.dll.
     return 0;
 #else
     RequestArcPassword();
@@ -582,7 +583,7 @@ size_t Archive::ReadHeader50()
 
   if (Decrypt)
   {
-#if defined(RAR_NOCRYPT)
+#if defined(RAR_NOCRYPT) || defined(CHROMIUM_UNRAR)
     return 0;
 #else