Restore a collapsed leading space of text used for line break

third_party/WebKit/Source/core/editing/iterators/TextIterator.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2005 Alexey Proskuryakov.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 593 matching lines @@
                     // See bug crbug.com/317365.
                     if (layoutObject->style()->whiteSpace() == PRE_LINE)
                         spliceBuffer('\n', m_node, 0, runStart, runStart);
                     else
                         spliceBuffer(spaceCharacter, m_node, 0, runStart, runStart + 1);
                     m_offset = runStart + 1;
                 } else {
                     size_t subrunEnd = str.find('\n', runStart);
                     if (subrunEnd == kNotFound || subrunEnd > runEnd) {
                         subrunEnd = runEnd;
-                        // Restore the collapsed trailing space for copy & paste.
+                        // Restore the collapsed space for copy & paste.
                         // See http://crbug.com/318925
+                        // For trailing space.
                         if (!nextTextBox && m_textBox->root().nextRootBox() && m_textBox->root().lastChild() == m_textBox) {
                             if (str.endsWith(' ') && subrunEnd == str.length() - 1 && str[subrunEnd - 1] != ' ')
                                 ++subrunEnd;
                         }
+                        // For leading space.
+                        if (m_textBox->root().prevRootBox() && m_textBox->root().firstChild() == m_textBox) {
+                            InlineBox* lastChildOfPrevRoot = m_textBox->root().prevRootBox()->lastChild();
+                            if (!lastChildOfPrevRoot->isText() && !lastChildOfPrevRoot->getLineLayoutItem().isBR()
+                                && !lastChildOfPrevRoot->isInlineFlowBox()) {
+                                if (runStart > 0 && str[0] == ' ')
+                                    --runStart;
+                            }
+                        }
                     }
 
                     m_offset = subrunEnd;
                     emitText(m_node, layoutObject, runStart, subrunEnd);
                 }
 
                 // If we are doing a subrun that doesn't go to the end of the text box,
                 // come back again to finish handling this text box; don't advance to the next one.
                 if (static_cast<unsigned>(m_textState.positionEndOffset()) < textBoxEnd)
                     return;
@@ skipping 585 matching lines @@
     if (range.isNull())
         return emptyString();
     DocumentLifecycle::DisallowTransitionScope disallowTransition(range.startPosition().document()->lifecycle());
     return createPlainText<EditingInFlatTreeStrategy>(range, behavior);
 }
 
 template class CORE_TEMPLATE_EXPORT TextIteratorAlgorithm<EditingStrategy>;
 template class CORE_TEMPLATE_EXPORT TextIteratorAlgorithm<EditingInFlatTreeStrategy>;
 
 } // namespace blink