clang-format: Fix corner case with comment in ctor initializer.

Formatting:
  Constructor() :
      // Comment forcing unwanted break.
      aaaa(aaaa) {}

Before:
  Constructor()
      :
        // Comment forcing unwanted break.
        aaaa(aaaa) {}

After:
  Constructor()
      : // Comment forcing unwanted break.
        aaaa(aaaa) {}

llvm-svn: 199107
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 3d73d47..08a7776 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -2896,6 +2896,13 @@
                "    : aaaaa(aaaaaaaaaaaaaaaaaaaaaa, aaaaaaaaaaaaaaaaaaaaaa,\n"
                "            aaaaaaaaaaaaaaaaaaaaaa) {}",
                OnePerLine);
+
+  EXPECT_EQ("Constructor()\n"
+            "    : // Comment forcing unwanted break.\n"
+            "      aaaa(aaaa) {}",
+            format("Constructor() :\n"
+                   "    // Comment forcing unwanted break.\n"
+                   "    aaaa(aaaa) {}"));
 }
 
 TEST_F(FormatTest, MemoizationTests) {