Have Document::markers() return a reference

Source/core/editing/TextCheckingHelper.cpp

 /*
  * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  *
  * 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 253 matching lines @@
                 RefPtr<Range> misspellingRange = TextIterator::subrange(m_range.get(), currentChunkOffset + misspellingLocation, misspellingLength);
 
                 // Remember first-encountered misspelling and its offset.
                 if (!firstMisspelling) {
                     firstMisspellingOffset = currentChunkOffset + misspellingLocation;
                     firstMisspelling = it.substring(misspellingLocation, misspellingLength);
                     firstMisspellingRange = misspellingRange;
                 }
 
                 // Store marker for misspelled word.
-                misspellingRange->startContainer()->document().markers()->addMarker(misspellingRange.get(), DocumentMarker::Spelling);
+                misspellingRange->startContainer()->document().markers().addMarker(misspellingRange.get(), DocumentMarker::Spelling);
 
                 // Bail out if we're marking only the first misspelling, and not all instances.
                 if (!markAll)
                     break;
             }
         }
 
         currentChunkOffset += length;
         it.advance();
     }
@@ skipping 140 matching lines @@
         // Skip this detail if it starts before the original search range
         if (detailStartOffsetInParagraph < startOffset)
             continue;
 
         // Skip this detail if it starts after the original search range
         if (detailStartOffsetInParagraph >= endOffset)
             continue;
 
         if (markAll) {
             RefPtr<Range> badGrammarRange = TextIterator::subrange(m_range.get(), badGrammarPhraseLocation - startOffset + detail->location, detail->length);
-            badGrammarRange->startContainer()->document().markers()->addMarker(badGrammarRange.get(), DocumentMarker::Grammar, detail->userDescription);
+            badGrammarRange->startContainer()->document().markers().addMarker(badGrammarRange.get(), DocumentMarker::Grammar, detail->userDescription);
         }
 
         // Remember this detail only if it's earlier than our current candidate (the details aren't in a guaranteed order)
         if (earliestDetailIndex < 0 || earliestDetailLocationSoFar > detail->location) {
             earliestDetailIndex = i;
             earliestDetailLocationSoFar = detail->location;
         }
     }
 
     return earliestDetailIndex;
@@ skipping 123 matching lines @@
         return false;
 
     const Settings* settings = frame->settings();
     if (!settings)
         return false;
 
     return settings->unifiedTextCheckerEnabled();
 }
 
 }