surfaceflinger: pass RenderEngine into BufferLayerConsumer

Add RenderEngine::isCurrent to replace
BufferLayerConsumer::checkAndUpdateEglStateLocked.  Remove a
duplicated check in updateAndReleaseLocked.  Use
RenderEngine::checkErrors.

Test: SurfaceFlinger_test
Change-Id: I6b97534a41a855d101965b498cb1afa72404227e
diff --git a/services/surfaceflinger/RenderEngine/RenderEngine.cpp b/services/surfaceflinger/RenderEngine/RenderEngine.cpp
index f1415c9..314333f 100644
--- a/services/surfaceflinger/RenderEngine/RenderEngine.cpp
+++ b/services/surfaceflinger/RenderEngine/RenderEngine.cpp
@@ -157,6 +157,10 @@
     return GLExtensions::getInstance().hasImageCrop();
 }
 
+bool RenderEngine::isCurrent() const {
+    return mEGLDisplay == eglGetCurrentDisplay() && mEGLContext == eglGetCurrentContext();
+}
+
 bool RenderEngine::setCurrentSurface(const RE::Surface& surface) {
     bool success = true;
     EGLSurface eglSurface = surface.getEGLSurface();