Revert "Revert "[SurfaceFlinger] Add GPU protected content support.""

This reverts commit 78fb96f3f8b40cba6b9e2cb2b0c332a45798b522.
Reason for revert: Revert the revert with Fix.

BUG: 35315015
Test: Test with a hacked patch.
Test: Watch Youtube movie, verifed by force GPU composition.
Change-Id: Ic738b5f873dbff322473d4f999074dc35c8813c7
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index e6a43c5..a5ba054 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -5439,10 +5439,11 @@
         ALOGW("FB is protected: PERMISSION_DENIED");
         return PERMISSION_DENIED;
     }
+    auto& engine(getRenderEngine());
 
     // this binds the given EGLImage as a framebuffer for the
     // duration of this scope.
-    renderengine::BindNativeBufferAsFramebuffer bufferBond(getRenderEngine(), buffer);
+    renderengine::BindNativeBufferAsFramebuffer bufferBond(engine, buffer);
     if (bufferBond.getStatus() != NO_ERROR) {
         ALOGE("got ANWB binding error while taking screenshot");
         return INVALID_OPERATION;
@@ -5454,9 +5455,9 @@
     // dependent on the context's EGLConfig.
     renderScreenImplLocked(renderArea, traverseLayers, useIdentityTransform);
 
-    base::unique_fd syncFd = getRenderEngine().flush();
+    base::unique_fd syncFd = engine.flush();
     if (syncFd < 0) {
-        getRenderEngine().finish();
+        engine.finish();
     }
     *outSyncFd = syncFd.release();