FileURLToFilePath: Don't unescape '/' and '\\'.

net/base/filename_util_unittest.cc

Index: net/base/filename_util_unittest.cc
diff --git a/net/base/filename_util_unittest.cc b/net/base/filename_util_unittest.cc
index 5e3fb7e1c9f91fe59b5702ce274034d87c6ce5aa..5b99452f3504aa57270809b1990402d379337b37 100644
--- a/net/base/filename_util_unittest.cc
+++ b/net/base/filename_util_unittest.cc
@@ -239,6 +239,9 @@ TEST(FilenameUtilTest, FileURLConversion) {
     {L"\\\\foo\\bar.txt", "file:/foo/bar.txt"},
     {L"\\\\foo\\bar.txt", "file://foo\\bar.txt"},
     {L"C:\\foo\\bar.txt", "file:\\\\\\c:/foo/bar.txt"},
+    // %2f ('/') and %5c ('\\') are left alone by both GURL and
+    // FileURLToFilePath.
+    {L"C:\\foo%2f..%5cbar", "file:///C:\\foo%2f..%5cbar"},

[eroman, 2016/02/18 19:37:28]

What are the unescaping rules for %2e   (dot) ?

[mmenke, 2016/02/18 20:30:22]

Dots are unescaped in paths, since they have no magic meaning http or file URLs
(They may have a magic meaning to the OS for how to handle opening, but that's
another matter).

The periods removed in the other test I added are removed because of magic code
to sanitize a file name for download.

[eroman, 2016/02/18 21:17:22]

But dots do have a magical meaning, which is no less magical than slashes and
backslashes IMO.

GURL will collapse paths during canonicalization, so for instance
   foo/bar/../x ---> foo/x

Right?

This will also occur when the dots are percent escaped, as in %2e%2e.

So from a policy perspective I still don't really understand why we would choose
to unescape dots, but not slashes and backslashes.

Both have implications for how file paths are opened on disk.

I get that this CL is trying to at least match the consistency from the point of
view of GURL, and LGTM from that side. But as a larger policy I don't quite
understand why special preference for slashes but not dots.

 #elif defined(OS_POSIX)
     {L"/c:/foo/bar.txt", "file:/c:/foo/bar.txt"},
     {L"/c:/foo/bar.txt", "file:///c:/foo/bar.txt"},
@@ -253,6 +256,9 @@ TEST(FilenameUtilTest, FileURLConversion) {
     {L"/foo/bar.txt", "file:////foo////bar.txt"},
     {L"/c:/foo/bar.txt", "file:\\\\\\c:/foo/bar.txt"},
     {L"/c:/foo/bar.txt", "file:c:/foo/bar.txt"},
+    // %2f ('/') and %5c ('\\') are left alone by both GURL and
+    // FileURLToFilePath.
+    {L"/foo%2f..%5cbar", "file:///foo%2f..%5cbar"},
 //  We get these wrong because GURL turns back slashes into forward
 //  slashes.
 //  {L"/foo%5Cbar.txt", "file://foo\\bar.txt"},
@@ -785,6 +791,16 @@ TEST(FilenameUtilTest, GenerateFileName) {
      "image/jpeg",
      L"download",
      L"download" JPEG_EXT},
+    {// Escaped slash, backslash, and leading periods in file name. The periods
+     // should be removed, both slashes replaced with dashes.
+     __LINE__,
+     "http://www.google.com/..%2f%5ctest.html",
+     "",
+     "",
+     "",
+     "",
+     L"",
+     L"--test.html"},
   };
 
   // Tests filename generation.  Once the correct filename is