Paste PDF into the editor from clipboard using Chrome does not work

Summary

Paste PDF into the editor from clipboard using Chrome does not work.

Environment

• Confluence 1000.847.1 (Cloud), Confluence 6.0.3 (Server)
• Chrome 55.0.2883.95
• macOS Sierra

Steps to Reproduce

Scenario1

1. Copy a PDF file in Finder.app
2. Open a Confluence page in edit mode
3. Press Cmd + V in the Confluence page

Scenario2

1. Open Terminal.app
2. Execute the following commands

   $ defaults write com.apple.screencapture type pdf
   $ killall SystemUIServer
   

3. Press Command + Control + Shift + 3 to capture a screenshot into the clipboard
4. Open a Confluence page in edit mode
5. Press Cmd + C in the Confluence page

Expected Results

The paste from the clipboard should work correctly in the both scenario.

Actual Results

Scenario1

The PDF wasn't attached to the page and the filename is just pasted as a text.

Scenario2

The paste failed silently.
If we monitor the step in developer tools, we can see the following JavaScript error.

dollar.js:1 Uncaught TypeError: Cannot read property 'size' of null
    at Object.pasteFromEvent (dollar.js:1)
    at Object.onPaste (dollar.js:1)
    at Editor.<anonymous> (dollar.js:1)
    at Dispatcher.dispatch (dollar.js:1)
    at b (dollar.js:1)
    at DOMUtils.<anonymous> (dollar.js:1)
    at HTMLBodyElement.e (dollar.js:1)

When it comes to some of third-party apps, they try to store images as PDF when copying them into clipboard.
That's why these scenario should be also considered.

Notes

This problem might be caused by this browser's spec.
Even though we don't support pasting PDF from clipboard, it would be more user friendly if Confluence could show some error on the UI.

Workaround

Use the other browsers instead.