Only switch draw buffers if the extension is supported

gpu/command_buffer/service/gles2_cmd_decoder.cc

 // Copyright (c) 2012 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 "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
 #include <stdio.h>
 
 #include <algorithm>
 #include <list>
@@ skipping 5067 matching lines @@
   }
   GLbitfield clear_bits = 0;
   if (framebuffer->HasUnclearedColorAttachments()) {
     glClearColor(
         0.0f, 0.0f, 0.0f,
         (GLES2Util::GetChannelsForFormat(
              framebuffer->GetColorAttachmentFormat()) & 0x0008) != 0 ? 0.0f :
                                                                        1.0f);
     state_.SetDeviceColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
     clear_bits |= GL_COLOR_BUFFER_BIT;
-    framebuffer->PrepareDrawBuffersForClear();
+    if (feature_info_->feature_flags().ext_draw_buffers)
+      framebuffer->PrepareDrawBuffersForClear();
   }
 
   if (framebuffer->HasUnclearedAttachment(GL_STENCIL_ATTACHMENT) ||
       framebuffer->HasUnclearedAttachment(GL_DEPTH_STENCIL_ATTACHMENT)) {
     glClearStencil(0);
     state_.SetDeviceStencilMaskSeparate(GL_FRONT, kDefaultStencilMask);
     state_.SetDeviceStencilMaskSeparate(GL_BACK, kDefaultStencilMask);
     clear_bits |= GL_STENCIL_BUFFER_BIT;
   }
 
   if (framebuffer->HasUnclearedAttachment(GL_DEPTH_ATTACHMENT) ||
       framebuffer->HasUnclearedAttachment(GL_DEPTH_STENCIL_ATTACHMENT)) {
     glClearDepth(1.0f);
     state_.SetDeviceDepthMask(GL_TRUE);
     clear_bits |= GL_DEPTH_BUFFER_BIT;
   }
 
   state_.SetDeviceCapabilityState(GL_SCISSOR_TEST, false);
   glClear(clear_bits);
 
-  if ((clear_bits | GL_COLOR_BUFFER_BIT) != 0)
+  if ((clear_bits | GL_COLOR_BUFFER_BIT) != 0 &&
+      feature_info_->feature_flags().ext_draw_buffers)
     framebuffer->RestoreDrawBuffersAfterClear();
 
   framebuffer_manager()->MarkAttachmentsAsCleared(
       framebuffer, renderbuffer_manager(), texture_manager());
 
   RestoreClearState();
 
   if (target == GL_READ_FRAMEBUFFER_EXT) {
     glBindFramebufferEXT(GL_READ_FRAMEBUFFER_EXT, framebuffer->service_id());
     Framebuffer* draw_framebuffer =
@@ skipping 5809 matching lines @@
   }
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu