Bug 833889 - Part 1. Remove CSS properties even if it is default value. r=masayuki

When selected nodes are <span style="font-weight: normal;">A</span>, toggle bold inserts new span element into parent node like <span style="font-weight: bold;"><span style="font-weight: normal;">A</span><span>.  So bold isn't applied correctly.

IsCSSEquivalentToHTMLInlineStyleSet might return false even if style is applied.  Because it returns true that style isn't default value.  Since "font-weight: normal" is default property, it isn't removed.

So when style is already applied even if it is default value, we should remove it.

MozReview-Commit-ID: LgImkHRp9Ff

--HG--
extra : rebase_source : dd4d894495754a81abaf5a2aede1132056920beb
extra : histedit_source : 72d196cd9f90296eb00b97c1538704c714cc871c

editor/libeditor/CSSEditUtils.cpp

@@ -1243,6 +1243,44 @@ CSSEditUtils::IsCSSEquivalentToHTMLInlineStyleSet(
   return isSet;
 }
 
+bool
+CSSEditUtils::HaveCSSEquivalentStyles(
+                nsINode& aNode,
+                nsIAtom* aHTMLProperty,
+                nsIAtom* aHTMLAttribute,
+                StyleType aStyleType)
+{
+  nsAutoString valueString;
+  nsCOMPtr<nsINode> node = &aNode;
+  do {
+    // get the value of the CSS equivalent styles
+    nsresult rv =
+      GetCSSEquivalentToHTMLInlineStyleSet(node, aHTMLProperty, aHTMLAttribute,
+                                           valueString, aStyleType);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return false;
+    }
+
+    if (!valueString.IsEmpty()) {
+      return true;
+    }
+
+    if (nsGkAtoms::u != aHTMLProperty && nsGkAtoms::strike != aHTMLProperty) {
+      return false;
+    }
+
+    // unfortunately, the value of the text-decoration property is not
+    // inherited.
+    // that means that we have to look at ancestors of node to see if they
+    // are underlined
+
+    // set to null if it's not a dom element
+    node = node->GetParentElement();
+  } while (node);
+
+  return false;
+}
+
 void
 CSSEditUtils::SetCSSEnabled(bool aIsCSSPrefChecked)
 {

editor/libeditor/CSSEditUtils.h

@@ -213,7 +213,7 @@ public:
    *                                values (out).
    * @param aStyleType     [IN] eSpecified or eComputed.
    * @return               A boolean being true if the css properties are
-   *                       set.
+   *                       not same as initial value.
    */
   bool IsCSSEquivalentToHTMLInlineStyleSet(nsINode* aContent,
                                            nsIAtom* aProperty,
@@ -239,6 +239,29 @@ public:
                                            nsAString& aValue,
                                            StyleType aStyleType);
 
+  /**
+   * This is a kind of IsCSSEquivalentToHTMLInlineStyleSet.
+   * IsCSSEquivalentToHTMLInlineStyleSet returns whether the properties
+   * aren't same as initial value.  But this method returns whether the
+   * properties aren't set.
+   * If node is <span style="font-weight: normal"/>,
+   *  - IsCSSEquivalentToHTMLInlineStyleSet returns false.
+   *  - HaveCSSEquivalentStyles returns true.
+   *
+   * @param aNode          [IN] A DOM node.
+   * @param aHTMLProperty  [IN] An atom containing an HTML property.
+   * @param aAttribute     [IN] An atom to an attribute name or nullptr
+   *                            if irrelevant.
+   * @param aStyleType     [IN] eSpecified or eComputed.
+   * @return               A boolean being true if the css properties are
+   *                       not set.
+   */
+
+  bool HaveCSSEquivalentStyles(nsINode& aNode,
+                               nsIAtom* aProperty,
+                               nsIAtom* aAttribute,
+                               StyleType aStyleType);
+
   /**
    * Adds to the node the CSS inline styles equivalent to the HTML style
    * and return the number of CSS properties set by the call.

editor/libeditor/HTMLStyleEditor.cpp

@@ -778,22 +778,25 @@ HTMLEditor::RemoveStyleInside(nsIContent& aNode,
     // the HTML style defined by aProperty/aAttribute has a CSS equivalence in
     // this implementation for the node aNode; let's check if it carries those
     // css styles
-    nsCOMPtr<nsIAtom> attribute =
-      aAttribute ? NS_Atomize(*aAttribute) : nullptr;
-    nsAutoString propertyValue;
-    bool isSet = mCSSEditUtils->IsCSSEquivalentToHTMLInlineStyleSet(&aNode,
-      aProperty, attribute, propertyValue, CSSEditUtils::eSpecified);
-    if (isSet && aNode.IsElement()) {
-      // yes, tmp has the corresponding css declarations in its style attribute
-      // let's remove them
-      mCSSEditUtils->RemoveCSSEquivalentToHTMLStyle(aNode.AsElement(),
-                                                    aProperty,
-                                                    attribute,
-                                                    &propertyValue,
-                                                    false);
-      // remove the node if it is a span or font, if its style attribute is
-      // empty or absent, and if it does not have a class nor an id
-      RemoveElementIfNoStyleOrIdOrClass(*aNode.AsElement());
+    if (aNode.IsElement()) {
+      nsCOMPtr<nsIAtom> attribute =
+        aAttribute ? NS_Atomize(*aAttribute) : nullptr;
+      bool hasAttribute =
+        mCSSEditUtils->HaveCSSEquivalentStyles(
+                         aNode, aProperty, attribute, CSSEditUtils::eSpecified);
+      if (hasAttribute) {
+        // yes, tmp has the corresponding css declarations in its style
+        // attribute
+        // let's remove them
+        mCSSEditUtils->RemoveCSSEquivalentToHTMLStyle(aNode.AsElement(),
+                                                      aProperty,
+                                                      attribute,
+                                                      nullptr,
+                                                      false);
+        // remove the node if it is a span or font, if its style attribute is
+        // empty or absent, and if it does not have a class nor an id
+        RemoveElementIfNoStyleOrIdOrClass(*aNode.AsElement());
+      }
     }
   }