glDiscardFramebuffer() in GrGpuGL::discard uses invalid GLenum

src/gpu/gl/GrGpuGL.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "GrGpuGL.h"
 #include "GrGLStencilBuffer.h"
@@ skipping 1312 matching lines @@
                 static const GrGLenum attachments[] = { GR_GL_COLOR };
                 GL_CALL(InvalidateFramebuffer(GR_GL_FRAMEBUFFER, SK_ARRAY_COUNT(attachments),
                         attachments));
             } else {
                 static const GrGLenum attachments[] = { GR_GL_COLOR_ATTACHMENT0 };
                 GL_CALL(InvalidateFramebuffer(GR_GL_FRAMEBUFFER, SK_ARRAY_COUNT(attachments),
                         attachments));
             }
             break;
         case GrGLCaps::kDiscard_InvalidateFBType: {
-            static const GrGLenum attachments[] = { GR_GL_COLOR };
-            GL_CALL(DiscardFramebuffer(GR_GL_FRAMEBUFFER, SK_ARRAY_COUNT(attachments),
-                    attachments));
+            if (0 == glRT->renderFBOID()) {
+                //  When rendering to the default framebuffer the legal values for attachments
+                //  are GL_COLOR, GL_DEPTH, GL_STENCIL, ... rather than the various FBO attachment
+                //  types. See glDiscardFramebuffer() spec.
+                static const GrGLenum attachments[] = { GR_GL_COLOR };
+                GL_CALL(DiscardFramebuffer(GR_GL_FRAMEBUFFER, SK_ARRAY_COUNT(attachments),
+                        attachments));
+            } else {
+                static const GrGLenum attachments[] = { GR_GL_COLOR_ATTACHMENT0 };
+                GL_CALL(DiscardFramebuffer(GR_GL_FRAMEBUFFER, SK_ARRAY_COUNT(attachments),
+                        attachments));
+            }
             break;
         }
     }
     renderTarget->flagAsResolved();
 }
 
 
 void GrGpuGL::clearStencil() {
     if (NULL == this->getDrawState().getRenderTarget()) {
         return;
@@ skipping 1488 matching lines @@
             this->setVertexArrayID(gpu, 0);
         }
         int attrCount = gpu->glCaps().maxVertexAttributes();
         if (fDefaultVertexArrayAttribState.count() != attrCount) {
             fDefaultVertexArrayAttribState.resize(attrCount);
         }
         attribState = &fDefaultVertexArrayAttribState;
     }
     return attribState;
 }