Make it a compile error to use a crash key with no variable name.

base/debug/crash_logging_unittest.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/debug/crash_logging.h"
 
 #include <stddef.h>
 
 #include <map>
 #include <string>
@@ skipping 97 matching lines @@
 
 TEST_F(CrashLoggingTest, ScopedCrashKey) {
   const char kTestKey[] = "test-key";
   base::debug::CrashKey keys[] = { { kTestKey, 255 } };
   base::debug::InitCrashKeys(keys, arraysize(keys), 255);
 
   EXPECT_EQ(0u, key_values_->size());
   EXPECT_TRUE(key_values_->end() == key_values_->find(kTestKey));
   {
     base::debug::ScopedCrashKey scoped_crash_key(kTestKey, "value");
+    base::debug::ScopedCrashKey(kTestKey, "with no name");
     EXPECT_EQ("value", (*key_values_)[kTestKey]);
     EXPECT_EQ(1u, key_values_->size());
   }
   EXPECT_EQ(0u, key_values_->size());
   EXPECT_TRUE(key_values_->end() == key_values_->find(kTestKey));
 }
 
 TEST_F(CrashLoggingTest, InitSize) {
   base::debug::CrashKey keys[] = {
     { "chunked-3", 15 },
@@ skipping 48 matching lines @@
   EXPECT_EQ("wor", results[2]);
   EXPECT_EQ("ld",  results[3]);
 }
 
 TEST_F(CrashLoggingTest, ChunkRounding) {
   // If max_length=12 and max_chunk_length=5, there should be 3 chunks,
   // not 2.
   base::debug::CrashKey key = { "round", 12 };
   EXPECT_EQ(3u, base::debug::InitCrashKeys(&key, 1, 5));
 }