Clear mutable inline style when it is empty.

Source/core/css/VariablesIterator.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
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  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
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 #include "config.h"
 #include "core/css/VariablesIterator.h"
 
 #include "RuntimeEnabledFeatures.h"
 #include "core/css/CSSVariableValue.h"
 #include "core/css/StylePropertySet.h"
+#include "core/dom/Element.h"
 
 namespace WebCore {
 
-PassRefPtr<VariablesIterator> VariablesIterator::create(MutableStylePropertySet* propertySet)
+void AbstractVariablesIterator::initRemainingNames(

[eseidel, 2013/12/23 21:30:23]

Could this just be part of the AbstractVariablesIterator constructor?  If not,
is there a way we can ASSERT when implementors fail to call this method?

[chrishtr, 2013/12/23 22:06:46]

I think it can, per your other comment. Will fix.

[chrishtr, 2013/12/23 22:34:20]

Done.

+    const StylePropertySet* propertySet, AbstractVariablesIterator* iterator)
 {
-    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
     const size_t propertyCount = propertySet->propertyCount();
     size_t variableCount = 0;
     Vector<AtomicString> remainingNames(propertyCount);
     for (int i = propertyCount; i--; ) {
         const StylePropertySet::PropertyReference& property = propertySet->propertyAt(i);
         if (property.id() == CSSPropertyVariable)
             remainingNames[variableCount++] = toCSSVariableValue(property.value())->name();
     }
+    // FIXME: Make use of the Vector move constructor when rvalues are supported on all platforms.
     remainingNames.shrink(variableCount);
 
+    iterator->takeRemainingNames(remainingNames);
+}
+
+PassRefPtr<VariablesIterator> VariablesIterator::create(MutableStylePropertySet* propertySet)
+{
+    ASSERT(RuntimeEnabledFeatures::cssVariablesEnabled());
     RefPtr<VariablesIterator> iterator = adoptRef(new VariablesIterator(propertySet));
-    // FIXME: Make use of the Vector move constructor when rvalues are supported on all platforms.
-    iterator->takeRemainingNames(remainingNames);
+    AbstractVariablesIterator::initRemainingNames(propertySet, iterator.get());

[eseidel, 2013/12/23 21:30:23]

As I commented in a previous pass, it's uncommon to have ::create() do anything
besides wrap the new calls in an adoptRef.  That said, if this needs to be done
this way it's totally fine.  I would add a comment in the header next to
initRemainingNames() that all subclasses must call it, etc.

[chrishtr, 2013/12/23 22:34:20]

Done.

     return iterator.release();
 }
 
 String AbstractVariablesIterator::value() const
 {
     return propertySet()->variableValue(name());
 }
 
 void AbstractVariablesIterator::addedVariable(const AtomicString& name)
 {
@@ skipping 22 matching lines @@
 {
     if (!atEnd())
         m_remainingNames.removeLast();
     if (!m_newNames.isEmpty()) {
         m_remainingNames.appendVector(m_newNames);
         m_newNames.clear();
     }
 }
 
 } // namespace WebCore