Remove backend factories

gyp/gpu.gypi

 # Include this gypi to include all 'gpu' files
 # The parent gyp/gypi file must define
 #       'skia_src_path'     e.g. skia/trunk/src
 #       'skia_include_path' e.g. skia/trunk/include
 #
 # The skia build defines these in common_variables.gypi
 #
 {
   'variables': {
     'skgpu_sources': [
-      '<(skia_include_path)/gpu/GrBackendProcessorFactory.h',
       '<(skia_include_path)/gpu/GrBinHashKey.h',
       '<(skia_include_path)/gpu/GrClipData.h',
       '<(skia_include_path)/gpu/GrColor.h',
       '<(skia_include_path)/gpu/GrConfig.h',
       '<(skia_include_path)/gpu/GrContext.h',
       '<(skia_include_path)/gpu/GrCoordTransform.h',
       '<(skia_include_path)/gpu/GrFragmentProcessor.h',
       '<(skia_include_path)/gpu/GrFragmentStage.h',
       '<(skia_include_path)/gpu/GrGpuResource.h',
       '<(skia_include_path)/gpu/GrInvariantOutput.h',
       '<(skia_include_path)/gpu/GrPaint.h',
       '<(skia_include_path)/gpu/GrPathRendererChain.h',
       '<(skia_include_path)/gpu/GrProcessor.h',
       '<(skia_include_path)/gpu/GrProcessorUnitTest.h',
       '<(skia_include_path)/gpu/GrProgramElement.h',
       '<(skia_include_path)/gpu/GrGpuResourceRef.h',
       '<(skia_include_path)/gpu/GrRect.h',
       '<(skia_include_path)/gpu/GrRenderTarget.h',
       '<(skia_include_path)/gpu/GrResourceKey.h',
       '<(skia_include_path)/gpu/GrSurface.h',
       '<(skia_include_path)/gpu/GrShaderVar.h',
-      '<(skia_include_path)/gpu/GrTBackendProcessorFactory.h',
       '<(skia_include_path)/gpu/GrTexture.h',
       '<(skia_include_path)/gpu/GrTextureAccess.h',
       '<(skia_include_path)/gpu/GrTypes.h',
       '<(skia_include_path)/gpu/GrUserConfig.h',
       '<(skia_include_path)/gpu/GrXferProcessor.h',
 
       '<(skia_include_path)/gpu/gl/GrGLConfig.h',
       '<(skia_include_path)/gpu/gl/GrGLExtensions.h',
       '<(skia_include_path)/gpu/gl/GrGLFunctions.h',
       '<(skia_include_path)/gpu/gl/GrGLInterface.h',
@@ skipping 317 matching lines @@
     ],
     'skgpu_null_gl_sources': [
       '<(skia_src_path)/gpu/gl/GrGLCreateNullInterface.cpp',
 
       # Sk files
       '<(skia_src_path)/gpu/gl/SkNullGLContext.cpp',
       '<(skia_src_path)/gpu/gl/SkNullGLContext.h',
     ],
   },
 }