rewrite_to_chrome_style: Fix build with new clang, and a crash

- Don't crash when trying to determine if a method on a class defined in
  the global namespace is a Blink method.
- Fix the build when building with newer revisions of clang that have an
  isDefaulted() matcher.

BUG=none
R=danakj@chromium.org

Review URL: https://codereview.chromium.org/1652953004 .

Cr-Commit-Position: refs/heads/master@{#373120}

3 files changed, 14 insertions, 10 deletions

diff --git a/tools/clang/rewrite_to_chrome_style/RewriteToChromeStyle.cpp b/tools/clang/rewrite_to_chrome_style/RewriteToChromeStyle.cpp
index b703823..5733b2c 100644
--- a/tools/clang/rewrite_to_chrome_style/RewriteToChromeStyle.cpp
+++ b/tools/clang/rewrite_to_chrome_style/RewriteToChromeStyle.cpp
@@ -48,6 +48,18 @@ using llvm::StringRef;
 
 namespace {
 
+// Hack: prevent the custom isDefaulted() from conflicting with the one defined
+// in newer revisions of Clang.
+namespace internal_hack {
+
+// This is available in newer clang revisions... but alas, Chrome has not rolled
+// that far yet.
+AST_MATCHER(clang::FunctionDecl, isDefaulted) {
+  return Node.isDefaulted();
+}
+
+}  // namespace internal_hack
+
 const char kBlinkFieldPrefix[] = "m_";
 const char kBlinkStaticMemberPrefix[] = "s_";
 
@@ -58,7 +70,7 @@ AST_MATCHER(clang::FunctionDecl, isOverloadedOperator) {
 // A method is from Blink if it is from the Blink namespace or overrides a
 // method from the Blink namespace.
 bool IsBlinkMethod(const clang::CXXMethodDecl& decl) {
-  auto* namespace_decl = clang::cast_or_null<clang::NamespaceDecl>(
+  auto* namespace_decl = clang::dyn_cast_or_null<clang::NamespaceDecl>(
       decl.getParent()->getEnclosingNamespaceContext());
   if (namespace_decl && namespace_decl->getParent()->isTranslationUnit() &&
       (namespace_decl->getName() == "blink" ||
@@ -415,7 +427,7 @@ int main(int argc, const char* argv[]) {
           // compiler, such as a synthesized copy constructor.
           // This skips explicitly defaulted functions as well, but that's OK:
           // there's nothing interesting to rewrite in those either.
-          unless(hasAncestor(functionDecl(isDefaulted())))));
+          unless(hasAncestor(functionDecl(internal_hack::isDefaulted())))));
   auto decl_ref_matcher = id("expr", declRefExpr(to(var_decl_matcher)));
 
   MemberRewriter member_rewriter(&replacements);
diff --git a/tools/clang/rewrite_to_chrome_style/tests/methods-expected.cc b/tools/clang/rewrite_to_chrome_style/tests/methods-expected.cc
index fd34bde..1dc5ce4 100644
--- a/tools/clang/rewrite_to_chrome_style/tests/methods-expected.cc
+++ b/tools/clang/rewrite_to_chrome_style/tests/methods-expected.cc
@@ -55,8 +55,6 @@ void Task::DoTheWork() {
 
 }  // namespace blink
 
-namespace Moo {
-
 // Test that overrides from outside the Blink namespace are also updated.
 class BovineTask : public blink::Task {
  public:
@@ -82,5 +80,3 @@ void F() {
   void (blink::Task::*p3)() = &blink::Task::ReallyDoTheWork;
   void (BovineTask::*p4)() = &BovineTask::ReallyDoTheWork;
 }
-
-}  // namespace Moo
diff --git a/tools/clang/rewrite_to_chrome_style/tests/methods-original.cc b/tools/clang/rewrite_to_chrome_style/tests/methods-original.cc
index 1547030..b2d9381 100644
--- a/tools/clang/rewrite_to_chrome_style/tests/methods-original.cc
+++ b/tools/clang/rewrite_to_chrome_style/tests/methods-original.cc
@@ -59,8 +59,6 @@ void Task::doTheWork() {
 
 }  // namespace blink
 
-namespace Moo {
-
 // Test that overrides from outside the Blink namespace are also updated.
 class BovineTask : public blink::Task {
  public:
@@ -86,5 +84,3 @@ void F() {
   void (blink::Task::*p3)() = &blink::Task::reallyDoTheWork;
   void (BovineTask::*p4)() = &BovineTask::reallyDoTheWork;
 }
-
-}  // namespace Moo