Make scoped enums output streamable.

base/logging_unittest.cc

Index: base/logging_unittest.cc
diff --git a/base/logging_unittest.cc b/base/logging_unittest.cc
index 22fb855b62afea792fb1708b5948f79d8a1f2848..354f6c7d6fcc339d24792a48e392d96af076e6c6 100644
--- a/base/logging_unittest.cc
+++ b/base/logging_unittest.cc
@@ -2,8 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "base/compiler_specific.h"
 #include "base/logging.h"
+
+#include <sstream>
+
+#include "base/compiler_specific.h"
 #include "base/macros.h"
 
 #include "testing/gmock/include/gmock/gmock.h"
@@ -276,6 +279,26 @@ TEST_F(LoggingTest, CheckEqStatements) {
     CHECK_EQ(false, true);           // Unreached.
 }
 
+// Test that scoped enums can be logged.
+TEST_F(LoggingTest, ScopedEnum) {
+#if 0
+  std::ostringstream ss1;
+  // Default underlying type is int.
+  enum class SignedTestEnum {
+    Value = -1,
+  };
+  ss1 << SignedTestEnum::Value;
+  EXPECT_EQ("-1", ss1.str());
+
+  std::ostringstream ss2;
+  enum class UnsignedTestEnum : unsigned {
+    Value = -1,  // This is intentional.
+  };
+  ss2 << UnsignedTestEnum::Value;
+  EXPECT_EQ("0xffffffff", ss2.str());
+#endif
+}
+
 // Test that defining an operator<< for a type in a namespace doesn't prevent
 // other code in that namespace from calling the operator<<(ostream, wstring)
 // defined by logging.h. This can fail if operator<<(ostream, wstring) can't be