Introduce TextBuffer as Output Type of copyTextTo() for Text Iterators

third_party/WebKit/Source/core/editing/iterators/SimplifiedBackwardsTextIterator.h

Index: third_party/WebKit/Source/core/editing/iterators/SimplifiedBackwardsTextIterator.h
diff --git a/third_party/WebKit/Source/core/editing/iterators/SimplifiedBackwardsTextIterator.h b/third_party/WebKit/Source/core/editing/iterators/SimplifiedBackwardsTextIterator.h
index fa96a52f9c13386cb66fcb39b074b66bb84df7c4..4ebe432717e4c9975e22f9e1e053799b4eeec924 100644
--- a/third_party/WebKit/Source/core/editing/iterators/SimplifiedBackwardsTextIterator.h
+++ b/third_party/WebKit/Source/core/editing/iterators/SimplifiedBackwardsTextIterator.h
@@ -28,6 +28,7 @@
 
 #include "core/editing/Position.h"
 #include "core/editing/iterators/FullyClippedStateStack.h"
+#include "core/editing/iterators/TextBuffer.h"
 #include "core/editing/iterators/TextIteratorFlags.h"
 #include "platform/heap/Heap.h"
 
@@ -60,16 +61,9 @@ public:
     // Calculate the minimum |actualLength >= minLength| such that code units
     // with offset range [position, position + actualLength) are whole code
     // points. Prepend these code points to |output| and return |actualLength|.
-    template<typename BufferType>
-    int copyTextTo(BufferType& output, int position, int minLength) const
-    {
-        int copiedLength = isBetweenSurrogatePair(position + minLength) ? minLength + 1 : minLength;
-        copyCodeUnitsTo(output, position, copiedLength);
-        return copiedLength;
-    }
-
-    template<typename BufferType>
-    int copyTextTo(BufferType& output, int position = 0) const { return copyTextTo(output, position, m_textLength - position); }
+    int copyTextTo(BackwardsTextBuffer& output, int position, int minLength) const;
+    // TODO(xiaochengh): Avoid default parameters.
+    int copyTextTo(BackwardsTextBuffer& output, int position = 0) const;
 
     Node* startContainer() const;
     int endOffset() const;
@@ -92,21 +86,7 @@ private:
 
     // Prepend code units with offset range [position, position + copyLength)
     // to the output buffer.
-    template<typename BufferType>
-    void copyCodeUnitsTo(BufferType& output, int position, int copyLength) const
-    {
-        ASSERT(position >= 0);
-        ASSERT(copyLength >= 0);
-        ASSERT(position + copyLength <= m_textLength);
-        // Make sure there's no integer overflow.
-        ASSERT(position + copyLength >= position);
-        if (m_textLength == 0 || copyLength == 0)
-            return;
-        if (m_singleCharacterBuffer)
-            output.prepend(&m_singleCharacterBuffer, 1);
-        else
-            m_textContainer.prependTo(output, m_textOffset + m_textLength - position - copyLength, copyLength);
-    }
+    void copyCodeUnitsTo(BackwardsTextBuffer& output, int position, int copyLength) const;
 
     // Current position, not necessarily of the text being returned, but position
     // as we walk through the DOM tree.