Implemented clang-tidy configurability via .clang-tidy files.

Summary:
This adds a support for the .clang-tidy file reading using
FileOptionsProvider, -dump-config option, and changes tests to not depend on
default checks set.

Reviewers: klimek, bkramer, djasper

Reviewed By: djasper

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D5186

llvm-svn: 217155
diff --git a/clang-tools-extra/unittests/clang-tidy/ClangTidyTest.h b/clang-tools-extra/unittests/clang-tidy/ClangTidyTest.h
index a9c68d4..ffadc1f 100644
--- a/clang-tools-extra/unittests/clang-tidy/ClangTidyTest.h
+++ b/clang-tools-extra/unittests/clang-tidy/ClangTidyTest.h
@@ -45,8 +45,10 @@
                            const Twine &Filename = "input.cc",
                            ArrayRef<std::string> ExtraArgs = None) {
   T Check;
-  ClangTidyContext Context(
-      new DefaultOptionsProvider(ClangTidyGlobalOptions(), ClangTidyOptions()));
+  ClangTidyOptions Options;
+  Options.Checks = "*";
+  ClangTidyContext Context(llvm::make_unique<DefaultOptionsProvider>(
+      ClangTidyGlobalOptions(), Options));
   ClangTidyDiagnosticConsumer DiagConsumer(Context);
   Check.setContext(&Context);
   std::vector<std::string> ArgCXX11(1, "-std=c++11");