Remove RenderThread from EglManager

Refactor to make EglManager re-usable.

Test: hwuiunit passes, hwuimacro works

Change-Id: Ie8e9398c703fada1dc5d8baca5f42485eadea202
diff --git a/libs/hwui/renderthread/RenderThread.h b/libs/hwui/renderthread/RenderThread.h
index 689f518..4a1fd9e 100644
--- a/libs/hwui/renderthread/RenderThread.h
+++ b/libs/hwui/renderthread/RenderThread.h
@@ -103,6 +103,9 @@
     sk_sp<Bitmap> allocateHardwareBitmap(SkBitmap& skBitmap);
     void dumpGraphicsMemory(int fd);
 
+    void requireGlContext();
+    void destroyGlContext();
+
     /**
      * isCurrent provides a way to query, if the caller is running on
      * the render thread.