[RenderEngine] Generalize RenderEngine instance creation methods.

Currently we only have GLES20RenderEngine as the only RenderEngine, however, in
the future we may have Vulkan RenderEngine. This patch adds a property to
control the creation of RenderEngine.

BUG: 112585051
Test: Build, flash, run display validation
Change-Id: I546300e8977d079f2760bd182fe53f3170976d56
3 files changed