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

third_party/WebKit/Source/core/paint/InlineTextBoxPainter.cpp

Index: third_party/WebKit/Source/core/paint/InlineTextBoxPainter.cpp
diff --git a/third_party/WebKit/Source/core/paint/InlineTextBoxPainter.cpp b/third_party/WebKit/Source/core/paint/InlineTextBoxPainter.cpp
index c7e62a0106e8c9b0e26d1951828b3128130d2564..30b53803e6fda58ba2cc1c7594bcb5d29a200178 100644
--- a/third_party/WebKit/Source/core/paint/InlineTextBoxPainter.cpp
+++ b/third_party/WebKit/Source/core/paint/InlineTextBoxPainter.cpp
@@ -145,10 +145,7 @@ void InlineTextBoxPainter::paint(const PaintInfo& paintInfo, const LayoutPoint&
 
     // 2. Now paint the foreground, including text and decorations like underline/overline (in quirks mode only).
     int length = m_inlineTextBox.len();
-    StringView string = m_inlineTextBox.getLineLayoutItem().text().createView();
-    ASSERT(m_inlineTextBox.start() + length <= string.length());
-    if (static_cast<unsigned>(length) != string.length() || m_inlineTextBox.start())
-        string.narrow(m_inlineTextBox.start(), length);
+    StringView string = StringView(m_inlineTextBox.getLineLayoutItem().text(), m_inlineTextBox.start(), length);
     int maximumLength = m_inlineTextBox.getLineLayoutItem().textLength() - m_inlineTextBox.start();
 
     StringBuilder charactersWithHyphen;
@@ -437,10 +434,7 @@ void InlineTextBoxPainter::paintSelection(GraphicsContext& context, const Layout
     // If the text is truncated, let the thing being painted in the truncation
     // draw its own highlight.
     int length = m_inlineTextBox.truncation() != cNoTruncation ? m_inlineTextBox.truncation() : m_inlineTextBox.len();
-    StringView string = m_inlineTextBox.getLineLayoutItem().text().createView();
-
-    if (string.length() != static_cast<unsigned>(length) || m_inlineTextBox.start())
-        string.narrow(m_inlineTextBox.start(), length);
+    StringView string(m_inlineTextBox.getLineLayoutItem().text(), m_inlineTextBox.start(), static_cast<unsigned>(length));
 
     StringBuilder charactersWithHyphen;
     bool respectHyphen = ePos == length && m_inlineTextBox.hasHyphen();