Continue refactoring ThemeProvider usage for colors:

- simplify COLOR_FRAME call sites
- remove single-arg GetDefaultColor()
- move detached bookmark bar color logic from its own file to
ThemeService and ThemeProperties

BUG=568388

Review URL: https://codereview.chromium.org/1526813002

Cr-Commit-Position: refs/heads/master@{#365947}
14 files changed