[1/3 blink] Add force update on page load checkbox in DevTool's Sources panel.
[1/3 blink] Add force update on page load checkbox in DevTool's Sources panel.

https://crbug.com/500428#c8 describes the design of the data flow.

1/3 blink: This CL.
2/3 chromium: https://codereview.chromium.org/1309673007/
3/3 blink: https://codereview.chromium.org/1333593002/

BUG=500428

Review URL: https://codereview.chromium.org/1307743012

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@202100 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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