Implement color layers in RenderEngine::drawLayers

Next cl will be using buffer sources. Afterwards with proper test
coverage we can try baking into the composition loop to verify that
there's no regressions.

Bug: 118461793
Change-Id: I897f6f6dfadcc05d6fa09a11ffad240f67996ad6
Test: librenderengine_test
diff --git a/libs/renderengine/tests/Android.bp b/libs/renderengine/tests/Android.bp
index 051b8b6..9b483ef 100644
--- a/libs/renderengine/tests/Android.bp
+++ b/libs/renderengine/tests/Android.bp
@@ -31,6 +31,7 @@
         "libgui",
         "liblog",
         "libnativewindow",
+        "libsync",
         "libui",
         "libutils",
     ],