Update the clang plugin to optionally enforce rules for Blink code.

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 8820407095efd974f3d465f1b87f6edb3337a5e2..9b7793afe3b6380e49768743219c4b42ce2946c9 100644
--- a/tools/clang/plugins/ChromeClassTester.cpp
+++ b/tools/clang/plugins/ChromeClassTester.cpp
@@ -150,6 +150,16 @@ bool ChromeClassTester::InBannedDirectory(SourceLocation loc) {
   filename.insert(filename.begin(), '/');
 #endif
 
+  for (const std::string& allowed_dir : allowed_directories_) {
+    // If any of the allowed directories occur as a component in filename,
+    // this file is allowed.
+    assert(allowed_dir.front() == '/' && "Allowed dir must start with '/'");
+    assert(allowed_dir.back() == '/' && "Allowed dir must end with '/'");
+
+    if (filename.find(allowed_dir) != std::string::npos)
+      return false;
+  }
+
   for (const std::string& banned_dir : banned_directories_) {
     // If any of the banned directories occur as a component in filename,
     // this file is rejected.
@@ -191,75 +201,79 @@ bool ChromeClassTester::InImplementationFile(SourceLocation record_location) {
 }
 
 void ChromeClassTester::BuildBannedLists() {
-  banned_namespaces_.push_back("std");
-  banned_namespaces_.push_back("__gnu_cxx");
+  banned_namespaces_.emplace("std");
+  banned_namespaces_.emplace("__gnu_cxx");
+
+  if (!options_.enforce_overriding_blink) {
+    banned_namespaces_.emplace("blink");
+    banned_namespaces_.emplace("WTF");
+  }
 
-  if (!options_.enforce_blink) {
-    banned_namespaces_.push_back("blink");
-    banned_namespaces_.push_back("WTF");
+  if (options_.enforce_in_thirdparty_webkit) {
+    allowed_directories_.emplace("/third_party/WebKit/");
   }
 
-  banned_directories_.push_back("/third_party/");
-  banned_directories_.push_back("/native_client/");
-  banned_directories_.push_back("/breakpad/");
-  banned_directories_.push_back("/courgette/");
-  banned_directories_.push_back("/pdf/");
-  banned_directories_.push_back("/ppapi/");
-  banned_directories_.push_back("/usr/include/");
-  banned_directories_.push_back("/usr/lib/");
-  banned_directories_.push_back("/usr/local/include/");
-  banned_directories_.push_back("/usr/local/lib/");
-  banned_directories_.push_back("/testing/");
-  banned_directories_.push_back("/v8/");
-  banned_directories_.push_back("/dart/");
-  banned_directories_.push_back("/sdch/");
-  banned_directories_.push_back("/icu4c/");
-  banned_directories_.push_back("/frameworks/");
+  banned_directories_.emplace("/third_party/");
+  banned_directories_.emplace("/native_client/");
+  banned_directories_.emplace("/breakpad/");
+  banned_directories_.emplace("/courgette/");
+  banned_directories_.emplace("/pdf/");
+  banned_directories_.emplace("/ppapi/");
+  banned_directories_.emplace("/usr/include/");
+  banned_directories_.emplace("/usr/lib/");
+  banned_directories_.emplace("/usr/local/include/");
+  banned_directories_.emplace("/usr/local/lib/");
+  banned_directories_.emplace("/testing/");
+  banned_directories_.emplace("/v8/");
+  banned_directories_.emplace("/dart/");
+  banned_directories_.emplace("/sdch/");
+  banned_directories_.emplace("/icu4c/");
+  banned_directories_.emplace("/frameworks/");
 
   // Don't check autogenerated headers.
   // Make puts them below $(builddir_name)/.../gen and geni.
   // Ninja puts them below OUTPUT_DIR/.../gen
   // Xcode has a fixed output directory for everything.
-  banned_directories_.push_back("/gen/");
-  banned_directories_.push_back("/geni/");
-  banned_directories_.push_back("/xcodebuild/");
+  banned_directories_.emplace("/gen/");
+  banned_directories_.emplace("/geni/");
+  banned_directories_.emplace("/xcodebuild/");
 
   // Used in really low level threading code that probably shouldn't be out of
   // lined.
-  ignored_record_names_.insert("ThreadLocalBoolean");
+  ignored_record_names_.emplace("ThreadLocalBoolean");
 
   // A complicated pickle derived struct that is all packed integers.
-  ignored_record_names_.insert("Header");
+  ignored_record_names_.emplace("Header");
 
   // Part of the GPU system that uses multiple included header
   // weirdness. Never getting this right.
-  ignored_record_names_.insert("Validators");
+  ignored_record_names_.emplace("Validators");
 
   // Has a UNIT_TEST only constructor. Isn't *terribly* complex...
-  ignored_record_names_.insert("AutocompleteController");
-  ignored_record_names_.insert("HistoryURLProvider");
+  ignored_record_names_.emplace("AutocompleteController");
+  ignored_record_names_.emplace("HistoryURLProvider");
 
   // Used over in the net unittests. A large enough bundle of integers with 1
   // non-pod class member. Probably harmless.
-  ignored_record_names_.insert("MockTransaction");
+  ignored_record_names_.emplace("MockTransaction");
 
   // Enum type with _LAST members where _LAST doesn't mean last enum value.
-  ignored_record_names_.insert("ServerFieldType");
+  ignored_record_names_.emplace("ServerFieldType");
 
   // Used heavily in ui_base_unittests and once in views_unittests. Fixing this
   // isn't worth the overhead of an additional library.
-  ignored_record_names_.insert("TestAnimationDelegate");
+  ignored_record_names_.emplace("TestAnimationDelegate");
 
   // Part of our public interface that nacl and friends use. (Arguably, this
   // should mean that this is a higher priority but fixing this looks hard.)
-  ignored_record_names_.insert("PluginVersionInfo");
+  ignored_record_names_.emplace("PluginVersionInfo");
 
   // Measured performance improvement on cc_perftests. See
   // https://codereview.chromium.org/11299290/
-  ignored_record_names_.insert("QuadF");
+  ignored_record_names_.emplace("QuadF");
 
   // Enum type with _LAST members where _LAST doesn't mean last enum value.
-  ignored_record_names_.insert("ViewID");
+  ignored_record_names_.emplace("ViewID");
 }
 
 std::string ChromeClassTester::GetNamespaceImpl(const DeclContext* context,