Change ChooserBubbleDelegate class name to ChooserBubbleController

This patch changed ChooserBubbleDelegate class name to
ChooserBubbleController since it better reflects the class's
responsibilities and clarifies the roles of the class.

BUG=492204, 588933

Review URL: https://codereview.chromium.org/1724183005

Cr-Commit-Position: refs/heads/master@{#377989}
16 files changed