Migrate screenshot methods to AIDL

Additonal service, named as "SurfaceFlingerAIDL", is added to surfaceflinger during the process of migrating ISurfaceComposer interface to AIDL. New changes are put into namespace, android::gui. Once migration is complete, this service will be deleted.

This CL migrates Screenshot methods to AIDL, more will come.

Bug: 211037638
Test: screencap
Change-Id: Idee91fa2444646639735847b1c76e983af39227f
diff --git a/services/surfaceflinger/main_surfaceflinger.cpp b/services/surfaceflinger/main_surfaceflinger.cpp
index caeff4a..ec18054 100644
--- a/services/surfaceflinger/main_surfaceflinger.cpp
+++ b/services/surfaceflinger/main_surfaceflinger.cpp
@@ -152,6 +152,11 @@
     sm->addService(String16(SurfaceFlinger::getServiceName()), flinger, false,
                    IServiceManager::DUMP_FLAG_PRIORITY_CRITICAL | IServiceManager::DUMP_FLAG_PROTO);
 
+    // publish gui::ISurfaceComposer, the new AIDL interface
+    sp<SurfaceComposerAIDL> composerAIDL = new SurfaceComposerAIDL(flinger);
+    sm->addService(String16("SurfaceFlingerAIDL"), composerAIDL, false,
+                   IServiceManager::DUMP_FLAG_PRIORITY_CRITICAL | IServiceManager::DUMP_FLAG_PROTO);
+
     startDisplayService(); // dependency on SF getting registered above
 
     if (SurfaceFlinger::setSchedFifo(true) != NO_ERROR) {