Make InlineBox::renderer() and related subclass methods return reference.

Source/core/editing/TextIterator.cpp

Index: Source/core/editing/TextIterator.cpp
diff --git a/Source/core/editing/TextIterator.cpp b/Source/core/editing/TextIterator.cpp
index a0e041e37711a138cb41304f1836e854b95ce80b..3bdbfc4964024dd00b4d953193719d2d5883fd3a 100644
--- a/Source/core/editing/TextIterator.cpp
+++ b/Source/core/editing/TextIterator.cpp
@@ -652,7 +652,7 @@ void TextIterator::handleTextBox()
         } else {
             nextTextBox = m_textBox->nextTextBox();
         }
-        ASSERT(!nextTextBox || nextTextBox->renderer() == renderer);
+        ASSERT(!nextTextBox || &nextTextBox->renderer() == renderer);
 
         if (runStart < runEnd) {
             // Handle either a single newline character (which becomes a space),