Fix compilation error on Windows

src/main/cpp/util/file_platform.h

@@ -100,6 +100,7 @@ bool ReadFile(const Path &filename, std::string *content,
 // There must be enough memory allocated at `data`.
 // Returns true on success, false on error.
 bool ReadFile(const std::string &filename, void *data, size_t size);
+bool ReadFile(const Path &filename, void *data, size_t size);
 
 // Writes `size` bytes from `data` into file `filename` and chmods it to `perm`.
 // Returns false on failure, sets errno.

src/main/cpp/util/file_posix.cc

@@ -219,6 +219,10 @@ bool ReadFile(const string &filename, void *data, size_t size) {
   return result;
 }
 
+bool ReadFile(const Path &filename, void *data, size_t size) {
+  return ReadFile(filename.AsNativePath(), data, size);
+}
+
 bool WriteFile(const void *data, size_t size, const string &filename,
                unsigned int perm) {
   UnlinkPath(filename);  // We don't care about the success of this.

src/main/cpp/util/file_windows.cc

@@ -303,15 +303,19 @@ bool ReadFile(const Path &path, std::string *content, int max_size) {
 }
 
 bool ReadFile(const string& filename, void* data, size_t size) {
-  if (filename.empty()) {
+  return ReadFile(Path(filename), data, size);
+}
+
+bool ReadFile(const Path &path, void *data, size_t size) {
+  if (path.IsEmpty()) {
     return false;
   }
-  if (IsDevNull(filename.c_str())) {
+  if (path.IsNull()) {
     // mimic read(2) behavior: we can always read 0 bytes from /dev/null
     return true;
   }
   HANDLE handle;
-  if (!OpenFileForReading(filename, &handle)) {
+  if (!OpenFileForReading(path, &handle)) {
     return false;
   }