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

third_party/WebKit/Source/platform/text/mac/HyphenationMac.cpp

Index: third_party/WebKit/Source/platform/text/mac/HyphenationMac.cpp
diff --git a/third_party/WebKit/Source/platform/text/mac/HyphenationMac.cpp b/third_party/WebKit/Source/platform/text/mac/HyphenationMac.cpp
index 0792e3db8c1602217487d4befa2427360ae252e1..40b298236da9571a9d65289a4649a794f6289ba3 100644
--- a/third_party/WebKit/Source/platform/text/mac/HyphenationMac.cpp
+++ b/third_party/WebKit/Source/platform/text/mac/HyphenationMac.cpp
@@ -20,7 +20,7 @@ public:
     size_t lastHyphenLocation(const StringView& text, size_t beforeIndex) const override
     {
         CFIndex result = CFStringGetHyphenationLocationBeforeIndex(
-            text.toString()->createCFString().get(), beforeIndex,
+            text.toString().impl()->createCFString().get(), beforeIndex,
             CFRangeMake(0, text.length()), 0, m_localeCF.get(), 0);
         return result == kCFNotFound ? 0 : result;
     }