Always report bounding rects even if caption bg appearance is opaque

To allows the apps to make the decision of whether to apply a background
caption bar appearance based on the available space determined by the
reported bounding rects.

Bug: 328667385
Test: atest DesktopModeWindowDecorationTests
Change-Id: Ic5048d7e528735774abff24de115e84f7b200963
2 files changed