DevTools: fix offset condition in console viewport _selectedText and add tests

third_party/WebKit/Source/devtools/front_end/console/ConsoleViewport.js

Index: third_party/WebKit/Source/devtools/front_end/console/ConsoleViewport.js
diff --git a/third_party/WebKit/Source/devtools/front_end/console/ConsoleViewport.js b/third_party/WebKit/Source/devtools/front_end/console/ConsoleViewport.js
index 6341e4a282ddb72bbbaf8150037b429c1ee1f4e5..f61e49ac56524a6c1de5c8a6de0b13ffec6198e1 100644
--- a/third_party/WebKit/Source/devtools/front_end/console/ConsoleViewport.js
+++ b/third_party/WebKit/Source/devtools/front_end/console/ConsoleViewport.js
@@ -466,9 +466,9 @@ Console.ConsoleViewport = class {
         continue;
       chars += Components.Linkifier.untruncatedNodeText(node).length;
     }
-    // If the selection offset is at the end of a link's ellipsis, use the untruncated length as offset.
+    // If the selected node text was truncated, treat any non-zero offset as the full length.
     var untruncatedContainerLength = Components.Linkifier.untruncatedNodeText(selectionNode).length;
-    if (offset === 1 && untruncatedContainerLength > offset)
+    if (offset > 0 && untruncatedContainerLength !== selectionNode.textContent.length)
       offset = untruncatedContainerLength;
     return chars + offset;
   }