Disable dual source blending support when GLSL version is too old

src/gpu/gl/GrGLCaps.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "GrGLCaps.h"
 
@@ skipping 966 matching lines @@
         else {
             fPathRenderingSupport = ctxInfo.version() >= GR_GL_VER(3, 1);
         }
     }
 
     // For now these two are equivalent but we could have dst read in shader via some other method
     fDstReadInShaderSupport = fFBFetchSupport;
 
     // Enable supported shader-related caps
     if (kGL_GrGLStandard == standard) {
-        fDualSourceBlendingSupport = ctxInfo.version() >= GR_GL_VER(3, 3) ||
-            ctxInfo.hasExtension("GL_ARB_blend_func_extended");
+        fDualSourceBlendingSupport = (ctxInfo.version() >= GR_GL_VER(3, 3) ||
+            ctxInfo.hasExtension("GL_ARB_blend_func_extended")) &&
+            GrGLSLSupportsNamedFragmentShaderOutputs(ctxInfo.glslGeneration());
         fShaderDerivativeSupport = true;
         // we don't support GL_ARB_geometry_shader4, just GL 3.2+ GS
         fGeometryShaderSupport = ctxInfo.version() >= GR_GL_VER(3, 2) &&
             ctxInfo.glslGeneration() >= k150_GrGLSLGeneration;
     }
     else {
         fShaderDerivativeSupport = ctxInfo.version() >= GR_GL_VER(3, 0) ||
             ctxInfo.hasExtension("GL_OES_standard_derivatives");
     }
 
@@ skipping 122 matching lines @@
     if (fGeometryShaderSupport) {
         for (int p = 0; p < kGrSLPrecisionCount; ++p) {
             fFloatPrecisions[kGeometry_GrShaderType][p] = fFloatPrecisions[kVertex_GrShaderType][p];
         }
     }
 }