SF: Add support for screen captures

Add Layer::drawNow to support capturing portions
of the screen in the FE, as this is not tied
to vsync

Test: Compile/Run manually
Merged-Id: I0781d44240ae127a6e70b35282a02cbedfe36fe4
Change-Id: I0781d44240ae127a6e70b35282a02cbedfe36fe4
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index af53a32..2c0dec9 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -4748,7 +4748,7 @@
 
     traverseLayers([&](Layer* layer) {
         if (filtering) layer->setFiltering(true);
-        layer->draw(renderArea, useIdentityTransform);
+        layer->drawNow(renderArea, useIdentityTransform);
         if (filtering) layer->setFiltering(false);
     });
 }