Introduce TextureRegistry.ImageTexture and related machinery. Introduce ImageReaderPlatformViewRenderTarget. Introduce HardwareBufferExternalTextureGL and related machinery. NOTE: ImageReaderPlatformViewRenderTarget requires Android 26. NOTE: This CL does not enable using ImageReaderPlatformViewRenderTarget yet. Related https://github.com/flutter/flutter/issues/130892 --------- Co-authored-by: Jason Simmons <jsimmons@google.com>