Chrome Version       : 66.0.3359.102
OS Version: 10452.54.0
URLs (if applicable) :
Other browsers tested:
  Add OK or FAIL after other browsers where you have tested this issue:
     Safari:
    Firefox:
    IE/Edge:

What steps will reproduce the problem?
1. Switch to the Traditional Pinyin IME.
2. Navigate to drive.google.com.
3. Create a new doc.
4. Focus the document. Type the letter 'a'. A dropdown suggesting completions should appear.
5. Press [Tab]. The origin chip should now be focused.
6. Press [Shift]+[Tab]. The caret should appear in the document again.
7. Press [Backspace].

What is the expected result?
After step 5: 'a' should no longer be underlined, indicating a pending completion, since focus has moved out of the text area.
After step 7: 'a' should be deleted.

What happens instead of that?
After step 5: 'a is still underlined, as if a completion is still pending.
After step 7: 'a' is not deleted.

Please provide any additional information below. Attach a screenshot if
possible.

UserAgentString: Mozilla/5.0 (X11; CrOS x86_64 10452.54.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.102 Safari/537.36