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/ContainerLayer.h b/services/surfaceflinger/ContainerLayer.h
index 543f60a..50c0191 100644
--- a/services/surfaceflinger/ContainerLayer.h
+++ b/services/surfaceflinger/ContainerLayer.h
@@ -32,6 +32,7 @@
     const char* getTypeId() const override { return "ContainerLayer"; }
     void onDraw(const RenderArea& renderArea, const Region& clip,
                 bool useIdentityTransform) const override;
+    void drawNow(const RenderArea& renderArea, bool useIdentityTransform) const override;
     bool isVisible() const override;
 
     void setPerFrameData(const sp<const DisplayDevice>& displayDevice) override;