clang-format: Recognize single-line macro usages inside macros.

Before:
  #define LIST(L)                                                     \
    L(FirstElement) L(SecondElement) L(ThirdElement) L(FourthElement) \
        L(FifthElement)

After:
  #define LIST(L)    \
    L(FirstElement)  \
    L(SecondElement) \
    L(ThirdElement)  \
    L(FourthElement) \
    L(FifthElement)

llvm-svn: 198407
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 66b54ab..232a063 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -2198,6 +2198,17 @@
                    "  IPC_END_MESSAGE_MAP()\n"
                    "}"));
 
+  // Same inside macros.
+  EXPECT_EQ("#define LIST(L) \\\n"
+            "  L(A)          \\\n"
+            "  L(B)          \\\n"
+            "  L(C)",
+            format("#define LIST(L) \\\n"
+                   "  L(A) \\\n"
+                   "  L(B) \\\n"
+                   "  L(C)",
+                   getGoogleStyle()));
+
   // These must not be recognized as macros.
   EXPECT_EQ("int q() {\n"
             "  f(x);\n"