DevTools: [CSS] Add CSS.editRangeInStyleSheetText() to the protocol

Source/core/inspector/InspectorStyleSheet.cpp

Index: Source/core/inspector/InspectorStyleSheet.cpp
diff --git a/Source/core/inspector/InspectorStyleSheet.cpp b/Source/core/inspector/InspectorStyleSheet.cpp
index 7613072d65c6d2ac363843dbf8649e4313da0040..e94125add219e5852e8a88ffddd951cd17ba14d6 100644
--- a/Source/core/inspector/InspectorStyleSheet.cpp
+++ b/Source/core/inspector/InspectorStyleSheet.cpp
@@ -1557,6 +1557,19 @@ InspectorCSSId InspectorStyleSheet::ruleId(CSSStyleRule* rule) const
     return ruleOrStyleId(rule->style());
 }
 
+bool InspectorStyleSheet::lineNumberAndColumnToOffset(unsigned lineNumber, unsigned columnNumber, unsigned* offset) const
+{
+    OwnPtr<Vector<unsigned> > endings = lineEndings();
+    if (lineNumber >= endings->size())
+        return false;
+    unsigned charactersInLine = lineNumber > 0 ? endings->at(lineNumber) - endings->at(lineNumber - 1) - 1 : endings->at(0) - 1;
+    if (columnNumber > charactersInLine)
+        return false;
+    TextPosition position(OrdinalNumber::fromZeroBasedInt(lineNumber), OrdinalNumber::fromZeroBasedInt(columnNumber));
+    *offset = position.toOffsetPosition(*endings).zeroBasedInt();
+    return true;
+}
+
 void InspectorStyleSheet::revalidateStyle(CSSStyleDeclaration* pageStyle)
 {
     if (m_isRevalidating)