rewrite_to_chrome_style: associate replacements with the affected file

tools/clang/rewrite_to_chrome_style/EditTracker.cpp

Index: tools/clang/rewrite_to_chrome_style/EditTracker.cpp
diff --git a/tools/clang/rewrite_to_chrome_style/EditTracker.cpp b/tools/clang/rewrite_to_chrome_style/EditTracker.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..cd8228ebdf5844c6ba22c66f0e20b38226bfb3ee
--- /dev/null
+++ b/tools/clang/rewrite_to_chrome_style/EditTracker.cpp
@@ -0,0 +1,41 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "EditTracker.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include "llvm/Support/Path.h"
+#include "llvm/Support/raw_ostream.h"
+
+void EditTracker::Add(const clang::SourceManager& source_manager,
+                      clang::SourceLocation location,
+                      llvm::StringRef original_text,
+                      llvm::StringRef new_text) {
+  llvm::StringRef filename;
+  for (int i = 0; i < 10; i++) {
+    filename = source_manager.getFilename(location);
+    if (!filename.empty() || !location.isMacroID())
+      break;
+    // Otherwise, no filename and the SourceLocation is a macro ID. Look one
+    // level up the stack...
+    location = source_manager.getImmediateMacroCallerLoc(location);
+  }
+  assert(!filename.empty() && "Can't track edit with no filename!");
+  auto result = tracked_edits_.try_emplace(original_text);
+  if (result.second) {
+    result.first->getValue().new_text = new_text;
+  }
+  result.first->getValue().filenames.try_emplace(filename);
+}
+
+void EditTracker::SerializeTo(llvm::StringRef tag,
+                              llvm::raw_ostream& output) const {
+  for (const auto& edit : tracked_edits_) {
+    for (const auto& filename : edit.getValue().filenames) {
+      output << filename.getKey() << ":" << tag << ":" << edit.getKey() << ":"
+             << edit.getValue().new_text << "\n";
+    }
+  }
+}