CopyFile: add a C++ API

Having to swizzle to C strings all the time is a bit annoying.

Change-Id: I0b80877706e32e873e567685f6b471745da70311
Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/2396557
Reviewed-by: Mark Mentovai <mark@chromium.org>
diff --git a/src/client/linux/minidump_writer/minidump_writer_unittest.cc b/src/client/linux/minidump_writer/minidump_writer_unittest.cc
index ac93a34..d192e5c 100644
--- a/src/client/linux/minidump_writer/minidump_writer_unittest.cc
+++ b/src/client/linux/minidump_writer/minidump_writer_unittest.cc
@@ -521,7 +521,7 @@
   // Copy binary to a temp file.
   AutoTempDir temp_dir;
   string binpath = temp_dir.path() + "/linux-dumper-unittest-helper";
-  ASSERT_TRUE(CopyFile(helper_path.c_str(), binpath.c_str()))
+  ASSERT_TRUE(CopyFile(helper_path, binpath))
       << "Failed to copy " << helper_path << " to " << binpath;
   ASSERT_EQ(0, chmod(binpath.c_str(), 0755));
 
diff --git a/src/common/tests/file_utils.cc b/src/common/tests/file_utils.cc
index 1c04177..c1cbb39 100644
--- a/src/common/tests/file_utils.cc
+++ b/src/common/tests/file_utils.cc
@@ -96,6 +96,10 @@
   return result;
 }
 
+bool CopyFile(const std::string& from_path, const std::string& to_path) {
+  return CopyFile(from_path.c_str(), to_path.c_str());
+}
+
 bool ReadFile(const char* path, void* buffer, ssize_t* buffer_size) {
   int fd = HANDLE_EINTR(open(path, O_RDONLY));
   if (fd == -1) {
diff --git a/src/common/tests/file_utils.h b/src/common/tests/file_utils.h
index c98a9bf..3d1a9c6 100644
--- a/src/common/tests/file_utils.h
+++ b/src/common/tests/file_utils.h
@@ -33,9 +33,12 @@
 #ifndef COMMON_TESTS_FILE_UTILS_H_
 #define COMMON_TESTS_FILE_UTILS_H_
 
+#include <string>
+
 namespace google_breakpad {
 
 // Copies a file from |from_path| to |to_path|. Returns true on success.
+bool CopyFile(const std::string& from_path, const std::string& to_path);
 bool CopyFile(const char* from_path, const char* to_path);
 
 // Reads the content of a file at |path| into |buffer|. |buffer_size| specifies