Expand WTF::StringView's API to be more like StringPiece.

third_party/WebKit/Source/core/testing/UnionTypesTest.cpp

 // Copyright 2014 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 "core/testing/UnionTypesTest.h"
 
 #include "wtf/text/StringBuilder.h"
 
 namespace blink {
 
@@ skipping 57 matching lines @@
 }
 
 String UnionTypesTest::doubleOrStringArrayArg(HeapVector<DoubleOrString>& array)
 {
     if (!array.size())
         return "";
 
     StringBuilder builder;
     for (DoubleOrString& doubleOrString : array) {
         ASSERT(!doubleOrString.isNull());
-        if (doubleOrString.isDouble())
-            builder.append("double: " + String::numberToStringECMAScript(doubleOrString.getAsDouble()));
-        else if (doubleOrString.isString())
-            builder.append("string: " + doubleOrString.getAsString());
-        else
+        if (doubleOrString.isDouble()) {
+            builder.append("double: ");
+            builder.append(String::numberToStringECMAScript(doubleOrString.getAsDouble()));
+        } else if (doubleOrString.isString()) {
+            builder.append("string: ");
+            builder.append(doubleOrString.getAsString());
+        } else {
             ASSERT_NOT_REACHED();
+        }
         builder.append(", ");
     }
     return builder.substring(0, builder.length() - 2);
 }
 
 String UnionTypesTest::doubleOrStringSequenceArg(HeapVector<DoubleOrString>& sequence)
 {
     return doubleOrStringArrayArg(sequence);
 }
 
@@ skipping 59 matching lines @@
     builder.append("sequence: [");
     for (const String& item : sequence) {
         ASSERT(!item.isNull());
         builder.append(item);
         builder.append(", ");
     }
     return builder.substring(0, builder.length() - 2) + "]";
 }
 
 } // namespace blink