Clear mutable inline style when it is empty.

Source/core/dom/Element.cpp

Index: Source/core/dom/Element.cpp
diff --git a/Source/core/dom/Element.cpp b/Source/core/dom/Element.cpp
index ced2bd06440792fe0a24dbe5deac5b25b4f45e55..01d87205c9b8b28160d0ae03ceb5bd78816560e8 100644
--- a/Source/core/dom/Element.cpp
+++ b/Source/core/dom/Element.cpp
@@ -924,6 +924,14 @@ void Element::setSynchronizedLazyAttribute(const QualifiedName& name, const Atom
     setAttributeInternal(index, name, value, InSynchronizationOfLazyAttribute);
 }
 
+void Element::removeSynchronizedLazyAttribute(const QualifiedName& name)
+{
+    size_t index = elementData() ? elementData()->getAttributeItemIndex(name) : kNotFound;
+    if (index == kNotFound)
+        return;
+    removeAttributeInternal(index, InSynchronizationOfLazyAttribute);
+}
+
 ALWAYS_INLINE void Element::setAttributeInternal(size_t index, const QualifiedName& name, const AtomicString& newValue, SynchronizationOfLazyAttribute inSynchronizationOfLazyAttribute)
 {
     if (newValue.isNull()) {
@@ -3434,6 +3442,8 @@ void Element::synchronizeStyleAttributeInternal() const
     elementData()->m_styleAttributeIsDirty = false;
     if (const StylePropertySet* inlineStyle = this->inlineStyle())
         const_cast<Element*>(this)->setSynchronizedLazyAttribute(styleAttr, inlineStyle->asText());
+    else
+        const_cast<Element*>(this)->removeSynchronizedLazyAttribute(styleAttr);

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

I remember being in this code for the hasAttribute/style-resolve patch (which
you were kind enough to run with) and I can't remember if setAtribute('foo',
null) will actually execute a remove?  Is removeSynchronizedLazyAttribute
actually necessary?

(I remember thsi because I was confused as to if synchronizing lazy attributes
could ever cause them to be removed.  It seemed liek the current implementation
made that impossible by accident iirc.)

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

Will adjust this method to use setSynchronizedLazyAttribute always.

 }
 
 CSSStyleDeclaration* Element::style()
@@ -3456,6 +3466,13 @@ MutableStylePropertySet* Element::ensureMutableInlineStyle()
     return toMutableStylePropertySet(inlineStyle);
 }
 
+void Element::clearMutableInlineStyleIfEmpty()
+{
+    if (ensureMutableInlineStyle()->isEmpty()) {
+        ensureUniqueElementData()->m_inlineStyle.clear();
+    }
+}
+
 PropertySetCSSStyleDeclaration* Element::inlineStyleCSSOMWrapper()
 {
     if (!inlineStyle() || !inlineStyle()->hasCSSOMWrapper())
@@ -3564,7 +3581,7 @@ bool Element::removeInlineStyleProperty(CSSPropertyID propertyID)
 void Element::removeAllInlineStyleProperties()
 {
     ASSERT(isStyledElement());
-    if (!inlineStyle() || inlineStyle()->isEmpty())
+    if (!inlineStyle())
         return;
     ensureMutableInlineStyle()->clear();
     inlineStyleChanged();