Handle null baseStyle in getPropertiesNotIn

Source/core/editing/EditingStyle.cpp

Index: Source/core/editing/EditingStyle.cpp
diff --git a/Source/core/editing/EditingStyle.cpp b/Source/core/editing/EditingStyle.cpp
index 6e44f9af1d6196af24e7f72b7bed299f42c75d18..92e51d4d6524f539ca3cccccdbeea512df3741f2 100644
--- a/Source/core/editing/EditingStyle.cpp
+++ b/Source/core/editing/EditingStyle.cpp
@@ -1434,7 +1434,7 @@ StyleChange::StyleChange(EditingStyle* style, const Position& position)
 
     reconcileTextDecorationProperties(mutableStyle.get());
     if (!document->frame()->editor().shouldStyleWithCSS())
-        extractTextStyles(document, mutableStyle.get(), computedStyle->fixedPitchFontType());
+        extractTextStyles(document, mutableStyle.get(), computedStyle ? computedStyle->fixedPitchFontType() : NonFixedPitchFont);
 
     // Changing the whitespace style in a tab span would collapse the tab into a space.
     if (isTabHTMLSpanElementTextNode(position.deprecatedNode()) || isTabHTMLSpanElement((position.deprecatedNode())))
@@ -1578,8 +1578,9 @@ static bool fontWeightNeedsResolving(CSSValue* fontWeight)
 PassRefPtrWillBeRawPtr<MutableStylePropertySet> getPropertiesNotIn(StylePropertySet* styleWithRedundantProperties, CSSStyleDeclaration* baseStyle)
 {
     ASSERT(styleWithRedundantProperties);
-    ASSERT(baseStyle);
     RefPtrWillBeRawPtr<MutableStylePropertySet> result = styleWithRedundantProperties->mutableCopy();
+    if (!baseStyle)
+        return result.release();
 
     result->removeEquivalentProperties(baseStyle);