C++: Adds source extension for match_clif.bzl

Test is in https://github.com/bazelbuild/bazel/blob/f225af1f48f1adf33e45b6d2511c21093ba164bd/src/test/java/com/google/devtools/build/lib/rules/cpp/SkylarkCcCommonTest.java#L5314

RELNOTES:none
PiperOrigin-RevId: 261153569

src/main/java/com/google/devtools/build/lib/rules/cpp/CppFileTypes.java

@@ -29,12 +29,16 @@ public final class CppFileTypes {
   public static final FileType C_SOURCE = FileType.of(".c");
   public static final FileType OBJC_SOURCE = FileType.of(".m");
   public static final FileType OBJCPP_SOURCE = FileType.of(".mm");
+  public static final FileType CLIF_INPUT_PROTO = FileType.of(".ipb");
+  public static final FileType CLIF_OUTPUT_PROTO = FileType.of(".opb");
+
   public static final FileTypeSet ALL_C_CLASS_SOURCE =
       FileTypeSet.of(
           CppFileTypes.CPP_SOURCE,
           CppFileTypes.C_SOURCE,
           CppFileTypes.OBJCPP_SOURCE,
-          CppFileTypes.OBJC_SOURCE);
+          CppFileTypes.OBJC_SOURCE,
+          CppFileTypes.CLIF_INPUT_PROTO);
 
   // Filetypes that generate LLVM bitcode when -flto is specified.
   public static final FileTypeSet LTO_SOURCE =
@@ -196,9 +200,6 @@ public boolean apply(String path) {
   public static final FileType CPP_MODULE_MAP = FileType.of(".cppmap");
   public static final FileType CPP_MODULE = FileType.of(".pcm");
 
-  public static final FileType CLIF_INPUT_PROTO = FileType.of(".ipb");
-  public static final FileType CLIF_OUTPUT_PROTO = FileType.of(".opb");
-
   /** Predicate that matches all artifacts that can be used in an objc Clang module map. */
   public static final Predicate<Artifact> MODULE_MAP_HEADER =
       artifact -> {