The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/46ab10923ea52c1e02980027a5e098ae25e904b7

commit 46ab10923ea52c1e02980027a5e098ae25e904b7
Author: luoe <luoe@chromium.org>
Date: Wed Jun 07 23:52:09 2017

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

When selecting non-truncated text, the selection start offset == 1 and the
selected node has text length > 1, the viewport would return incorrect values
for _selectedText(). It should only use the untruncated offset when it differs
from the node's rendered text length.

This CL corrects the condition and adds tests for other cases.

BUG= 722497 

Review-Url: https://codereview.chromium.org/2900733003
Cr-Commit-Position: refs/heads/master@{#477809}

[add] https://crrev.com/46ab10923ea52c1e02980027a5e098ae25e904b7/third_party/WebKit/LayoutTests/inspector/console/console-copy-truncated-text-expected.txt
[add] https://crrev.com/46ab10923ea52c1e02980027a5e098ae25e904b7/third_party/WebKit/LayoutTests/inspector/console/console-copy-truncated-text.html
[modify] https://crrev.com/46ab10923ea52c1e02980027a5e098ae25e904b7/third_party/WebKit/Source/devtools/front_end/console/ConsoleViewport.js