Fix crash where trim memory resulted in HWUI deleting the surface.

When HWUI is given the TRIM_MEMORY_COMPLETE signal it deletes all
of the associated GPU resources. In doing so it also deleted the
GL/Vk handle to the the ANativeWindow. So if the app attempted to
recover and draw new content it would crash because we no longer
had a surface to reinitialize and render into.

Test: atest hwui_unit_tests
Bug: 233388563
Change-Id: I54f3f0dadc3dfc89d2b1f567d36611f6a966c4f0
diff --git a/libs/hwui/pipeline/skia/SkiaOpenGLPipeline.h b/libs/hwui/pipeline/skia/SkiaOpenGLPipeline.h
index 186998a..a80c613 100644
--- a/libs/hwui/pipeline/skia/SkiaOpenGLPipeline.h
+++ b/libs/hwui/pipeline/skia/SkiaOpenGLPipeline.h
@@ -61,7 +61,8 @@
 private:
     renderthread::EglManager& mEglManager;
     EGLSurface mEglSurface = EGL_NO_SURFACE;
-    bool mBufferPreserved = false;
+    sp<ANativeWindow> mNativeWindow;
+    renderthread::SwapBehavior mSwapBehavior = renderthread::SwapBehavior::kSwap_discardBuffer;
 };
 
 } /* namespace skiapipeline */