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 a08ead4bd5d39f6c885d0ec2f7648451d14464c5..e9a0bcac479cae3b7d87a100f87a1b5f9c812504 100644
--- a/tools/clang/plugins/ChromeClassTester.cpp
+++ b/tools/clang/plugins/ChromeClassTester.cpp
@@ -7,6 +7,8 @@
 
 #include "ChromeClassTester.h"
 
+#include <algorithm>
+
 #include "clang/AST/AST.h"
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/SourceManager.h"
@@ -232,6 +234,9 @@ std::string ChromeClassTester::GetNamespaceImpl(const DeclContext* context,
 }
 
 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
@@ -250,7 +255,7 @@ bool ChromeClassTester::InBannedDirectory(SourceLocation loc) {
     return true;
   }
 
-#ifdef LLVM_ON_UNIX
+#if defined(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.
@@ -260,6 +265,10 @@ bool ChromeClassTester::InBannedDirectory(SourceLocation loc) {
   }
 #endif
 
+#if defined(LLVM_ON_WIN32)
+  std::replace(filename.begin(), filename.end(), '\\', '/');
+#endif
+
   for (const std::string& banned_dir : banned_directories_) {
     // If any of the banned directories occur as a component in filename,
     // this file is rejected.