Revert of Build the Clang plugin on Windows.

tools/clang/plugins/ChromeClassTester.cpp

Index: tools/clang/plugins/ChromeClassTester.cpp
diff --git a/tools/clang/plugins/ChromeClassTester.cpp b/tools/clang/plugins/ChromeClassTester.cpp
index e9a0bcac479cae3b7d87a100f87a1b5f9c812504..a08ead4bd5d39f6c885d0ec2f7648451d14464c5 100644
--- a/tools/clang/plugins/ChromeClassTester.cpp
+++ b/tools/clang/plugins/ChromeClassTester.cpp
@@ -6,8 +6,6 @@
 // code.
 
 #include "ChromeClassTester.h"
-
-#include <algorithm>
 
 #include "clang/AST/AST.h"
 #include "clang/Basic/FileManager.h"
@@ -234,9 +232,6 @@
 }
 
 bool ChromeClassTester::InBannedDirectory(SourceLocation loc) {
-  if (instance().getSourceManager().isInSystemHeader(loc))
-    return true;
-
   std::string filename;
   if (!GetFilename(loc, &filename)) {
     // If the filename cannot be determined, simply treat this as a banned
@@ -255,7 +250,7 @@
     return true;
   }
 
-#if defined(LLVM_ON_UNIX)
+#ifdef LLVM_ON_UNIX
   // We need to munge the paths so that they are relative to the repository
   // srcroot. We first resolve the symlinktastic relative path and then
   // remove our known srcroot from it if needed.
@@ -263,10 +258,6 @@
   if (realpath(filename.c_str(), resolvedPath)) {
     filename = resolvedPath;
   }
-#endif
-
-#if defined(LLVM_ON_WIN32)
-  std::replace(filename.begin(), filename.end(), '\\', '/');
 #endif
 
   for (const std::string& banned_dir : banned_directories_) {