Make SVG elements not to consider editable.

Source/core/dom/Position.cpp

Index: Source/core/dom/Position.cpp
diff --git a/Source/core/dom/Position.cpp b/Source/core/dom/Position.cpp
index dacff4069ead02e8d5f39e0d2d15bf0d9294ea25..b989d7be26fe27b14deffa51dcd8952f0bc8fe6a 100644
--- a/Source/core/dom/Position.cpp
+++ b/Source/core/dom/Position.cpp
@@ -865,6 +865,12 @@ bool Position::isCandidate() const
     if (renderer->isText())
         return !nodeIsUserSelectNone(deprecatedNode()) && inRenderedText();
 
+    if (renderer->isSVG()) {
+        // We don't consider SVG elements are contenteditable except for
+        // associated renderer returns isText() true, e.g. RenderSVGInlineText.
+        return false;
+    }
+
     if (isRenderedTableElement(deprecatedNode()) || editingIgnoresContent(deprecatedNode()))
         return (atFirstEditingPositionForNode() || atLastEditingPositionForNode()) && !nodeIsUserSelectNone(deprecatedNode()->parentNode());