Lift VFS from clang to llvm (NFC)

This patch moves the virtual file system form clang to llvm so it can be
used by more projects.

Concretely the patch:
 - Moves VirtualFileSystem.{h|cpp} from clang/Basic to llvm/Support.
 - Moves the corresponding unit test from clang to llvm.
 - Moves the vfs namespace from clang::vfs to llvm::vfs.
 - Formats the lines affected by this change, mostly this is the result of
   the added llvm namespace.

RFC on the mailing list:
http://lists.llvm.org/pipermail/llvm-dev/2018-October/126657.html

Differential revision: https://reviews.llvm.org/D52783

llvm-svn: 344140

1 files changed, 2 insertions, 2 deletions

diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index b29f67addf8..86b1ca2f17d 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -12375,14 +12375,14 @@ TEST_F(FormatTest, NoSpaceAfterSuper) {
 }
 
 TEST(FormatStyle, GetStyleWithEmptyFileName) {
-  vfs::InMemoryFileSystem FS;
+  llvm::vfs::InMemoryFileSystem FS;
   auto Style1 = getStyle("file", "", "Google", "", &FS);
   ASSERT_TRUE((bool)Style1);
   ASSERT_EQ(*Style1, getGoogleStyle());
 }
 
 TEST(FormatStyle, GetStyleOfFile) {
-  vfs::InMemoryFileSystem FS;
+  llvm::vfs::InMemoryFileSystem FS;
   // Test 1: format file in the same directory.
   ASSERT_TRUE(
       FS.addFile("/a/.clang-format", 0,