Workaround NVIDIA driver bug with NV_sample_mask_override_coverage

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 678 matching lines @@
         glslCaps->fSampleVariablesSupport = ctxInfo.glslGeneration() >= k400_GrGLSLGeneration;
     } else {
         if (ctxInfo.glslGeneration() >= k320es_GrGLSLGeneration) {
             glslCaps->fSampleVariablesSupport = true;
         } else if (ctxInfo.hasExtension("GL_OES_sample_variables")) {
             glslCaps->fSampleVariablesSupport = true;
             glslCaps->fSampleVariablesExtensionString = "GL_OES_sample_variables";
         }
     }
 
-    if (glslCaps->fSampleVariablesSupport) {
+    if (glslCaps->fSampleVariablesSupport &&
+        ctxInfo.hasExtension("GL_NV_sample_mask_override_coverage")) {
+        // Pre-361 NVIDIA has a bug with NV_sample_mask_override_coverage.
         glslCaps->fSampleMaskOverrideCoverageSupport =
-            ctxInfo.hasExtension("GL_NV_sample_mask_override_coverage");
+            kNVIDIA_GrGLDriver != ctxInfo.driver() ||
+            ctxInfo.driverVersion() >= GR_GL_DRIVER_VER(361,00);
     }
 
     // Adreno GPUs have a tendency to drop tiles when there is a divide-by-zero in a shader
     glslCaps->fDropsTileOnZeroDivide = kQualcomm_GrGLVendor == ctxInfo.vendor();
 
     // On the NexusS and GalaxyNexus, the use of 'any' causes the compilation error "Calls to any
     // function that may require a gradient calculation inside a conditional block may return
     // undefined results". This appears to be an issue with the 'any' call since even the simple
     // "result=black; if (any()) result=white;" code fails to compile. This issue comes into play
     // from our GrTextureDomain processor.
@@ skipping 1211 matching lines @@
         for (int j = 0; j < kExternalFormatUsageCnt; ++j) {
             SkASSERT(defaultEntry.fFormats.fExternalFormat[j] !=
                      fConfigTable[i].fFormats.fExternalFormat[j]);
         }
         SkASSERT(defaultEntry.fFormats.fExternalType != fConfigTable[i].fFormats.fExternalType);
     }
 #endif
 }
 
 void GrGLCaps::onApplyOptionsOverrides(const GrContextOptions& options) {}