Revert "Revert "SF: Add support for screen captures""

This reverts commit 2156613b58e6a792e3ab504ed0b7a0b189ff041b.

Test: Manual and cts -m ViewTestCases

Change-Id: Ia1de956a2f41ecd3e019c8540a60d42c37bc343e
diff --git a/services/surfaceflinger/BufferLayer.h b/services/surfaceflinger/BufferLayer.h
index 7f5ff3f..0886f17 100644
--- a/services/surfaceflinger/BufferLayer.h
+++ b/services/surfaceflinger/BufferLayer.h
@@ -101,6 +101,7 @@
      */
     void onDraw(const RenderArea& renderArea, const Region& clip,
                 bool useIdentityTransform) const override;
+    void drawNow(const RenderArea& renderArea, bool useIdentityTransform) const;
 
     void onLayerDisplayed(const sp<Fence>& releaseFence) override;