[Mac] Resolve trybot flakiness: DCHECK fail when deleting GL shader programs.

content/browser/renderer_host/compositing_iosurface_shader_programs_mac.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/compositing_iosurface_shader_programs_mac.h"
 
 #include <string>
 #include <OpenGL/gl.h>
 
 #include "base/basictypes.h"
@@ skipping 340 matching lines @@
 #ifndef NDEBUG
   for (size_t i = 0; i < arraysize(shader_programs_); ++i)
     DCHECK_EQ(shader_programs_[i], 0u) << "Failed to call Reset().";
 #endif
 }
 
 void CompositingIOSurfaceShaderPrograms::Reset() {
   for (size_t i = 0; i < arraysize(shader_programs_); ++i) {
     if (shader_programs_[i] != 0u) {
       glDeleteProgram(shader_programs_[i]);
-      DCHECK(glGetError() == GL_NO_ERROR)
-          << "when calling glDeleteProgram(shader_programs_[" << i << "])";
       shader_programs_[i] = 0u;
     }
   }
   for (size_t i = 0; i < arraysize(texture_var_locations_); ++i)
     texture_var_locations_[i] = -1;
   for (size_t i = 0; i < arraysize(texel_scale_x_var_locations_); ++i)
     texel_scale_x_var_locations_[i] = -1;
 }
 
 bool CompositingIOSurfaceShaderPrograms::UseBlitProgram() {
@@ skipping 68 matching lines @@
   if (texel_scale_x_var_locations_[which] == -1) {
     texel_scale_x_var_locations_[which] =
         glGetUniformLocation(GetShaderProgram(which), "texel_scale_x_");
     DCHECK_NE(texel_scale_x_var_locations_[which], -1)
         << "Failed to find location of uniform variable: texel_scale_x_";
   }
   glUniform1f(texel_scale_x_var_locations_[which], texel_scale_x);
 }
 
 }  // namespace content