Add possibility to ignore unregistered crash keys. Use this from WebView

base/debug/crash_logging_unittest.cc

Index: base/debug/crash_logging_unittest.cc
diff --git a/base/debug/crash_logging_unittest.cc b/base/debug/crash_logging_unittest.cc
index 5197c03e272ccdec2dd38457ffa115bd59786ca5..1b8203ad66429bf330d91526963e6d2a49415643 100644
--- a/base/debug/crash_logging_unittest.cc
+++ b/base/debug/crash_logging_unittest.cc
@@ -183,3 +183,29 @@ TEST_F(CrashLoggingTest, ChunkRounding) {
   base::debug::CrashKey key = { "round", 12 };
   EXPECT_EQ(3u, base::debug::InitCrashKeys(&key, 1, 5));
 }
+
+TEST_F(CrashLoggingTest, IgnoreUnregisteredKeys) {
+  base::debug::CrashKey key1 = {"first", 10};
+  base::debug::CrashKey key2 = {"second", 10};
+  base::debug::CrashKey key3 = {"third", 10};
+  base::debug::CrashKey unregistered_key = {"unreg", 10};
+  base::debug::CrashKey keys[] = {key1, key2, key3};
+  std::map<std::string, std::string>& values = *key_values_;
+
+  size_t num_keys = base::debug::InitCrashKeys(
+      keys, arraysize(keys), 10, true /* ignore_unregistered_keys */);
+
+  EXPECT_EQ(3u, num_keys);
+
+  base::debug::SetCrashKeyValue(key1.key_name, "foo");
+  base::debug::SetCrashKeyValue(key2.key_name, "bar");
+  base::debug::SetCrashKeyValue(unregistered_key.key_name, "baro");
+  EXPECT_EQ(2u, values.size());
+  EXPECT_EQ("foo", values[key1.key_name]);
+  EXPECT_EQ("bar", values[key2.key_name]);
+  EXPECT_TRUE(values.end() == values.find(unregistered_key.key_name));
+
+  base::debug::SetCrashKeyValue(key3.key_name, "yup");
+  EXPECT_EQ(3u, values.size());
+  EXPECT_EQ("yup", values[key3.key_name]);
+}