[Home] Disable theme colors in toolbar
This change disabled theme colors in the toolbar when Chrome Home is
enabled. The primary mechanism for doing this overriding functionality
in the ToolbarDataProvider to always return a default theme color.
Since theme colors are still needed for the status and progress bars,
the tab still needs to retain knowledge of the web contents' theme.
In those cases, the tab is queried instead of the data provider (this
should be cleaned up once a decision is made to keep or remove
themes).
BUG=
718932
Review-Url:
https://codereview.chromium.org/2862113003
Cr-Commit-Position: refs/heads/master@{#470087}
Committed:
https://chromium.googlesource.com/chromium/src/+/f00e42fce417e8d5875914c16417333b10e73e1e