Android P系统输出图像镜像翻转实现

特殊需求，对Android的输出图像做镜像翻转。

Screen convert

翻转x修改

源码：frameworks/native/services/surfaceflinger/RenderEngine/ProgramCache.cpp

  String8 ProgramCache::generateVertexShader(const Key& needs) {
   
   
      Formatter vs;
      if (needs.isTexturing()) {
   
   
          vs << "attribute vec4 texCoords;"
             << "varying vec2 outTexCoords;";
      }
      vs << "attribute vec4 position;"
         << "uniform mat4 projection;"
         <<