Don't unescape backslashes in URLs, since these will be converted to slashes...

net/base/escape.cc

Index: net/base/escape.cc
===================================================================
--- net/base/escape.cc	(revision 68176)
+++ net/base/escape.cc	(working copy)
@@ -71,7 +71,8 @@
 //
 // The basic rule is that we can't unescape anything that would changing parsing
 // like # or ?. We also can't unescape &, =, or + since that could be part of a
-// query and that could change the server's parsing of the query.
+// query and that could change the server's parsing of the query. Nor can we
+// unescape \ since googleurl will convert it to a /.
 //
 // Lastly, we can't unescape anything that doesn't have a canonical
 // representation in a URL. This means that unescaping will change the URL, and
@@ -90,7 +91,7 @@
 //   @  A  B  C  D  E  F  G  H  I  J  K  L  M  N  O
      0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
 //   P  Q  R  S  T  U  V  W  X  Y  Z  [  \  ]  ^  _
-     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1,
+     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1,
 //   `  a  b  c  d  e  f  g  h  i  j  k  l  m  n  o
      1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
 //   p  q  r  s  t  u  v  w  x  y  z  {  |  }  ~  <NBSP>