Always wait at least 150ms before displaying the popup

Previously we would wait 150ms if the data was cached,
or 50ms + [API request time] if it was not.

Using some promise magic to achieve this without decreasing
performance. The behavior of sendRequest() was changed a bit.

Bug: 64235
Change-Id: Ibe6e1a5f4ac02f538dac686476ac95ba506a1a86