Fix crash in BlitFramebufferCHROMIUM if a read or draw depth/stencil buffer is not present

gpu/command_buffer/service/framebuffer_manager.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/framebuffer_manager.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/logging.h"
@@ skipping 674 matching lines @@
 GLsizei Framebuffer::GetSamples() const {
   // Assume the framebuffer is complete, so return any attachment's samples.
   auto iter = attachments_.begin();
   if (iter == attachments_.end())
     return -1;
   Attachment* attachment = iter->second.get();
   DCHECK(attachment);
   return attachment->samples();
 }
 
-GLenum Framebuffer::GetDepthFormat() const {
+const Framebuffer::Attachment* Framebuffer::GetDepthAttachment() const {
   auto iter = attachments_.find(GL_DEPTH_STENCIL_ATTACHMENT);
   if (iter == attachments_.end())
     iter = attachments_.find(GL_DEPTH_ATTACHMENT);
   if (iter == attachments_.end())
-    return 0;
+    return nullptr;
   Attachment* attachment = iter->second.get();
   DCHECK(attachment);
-  return attachment->internal_format();
+  return attachment;
 }
 
-GLenum Framebuffer::GetStencilFormat() const {
+const Framebuffer::Attachment* Framebuffer::GetStencilAttachment() const {
   auto iter = attachments_.find(GL_DEPTH_STENCIL_ATTACHMENT);
   if (iter == attachments_.end())
     iter = attachments_.find(GL_STENCIL_ATTACHMENT);
   if (iter == attachments_.end())
-    return 0;
+    return nullptr;
   Attachment* attachment = iter->second.get();
   DCHECK(attachment);
-  return attachment->internal_format();
+  return attachment;
+}
+
+GLenum Framebuffer::GetDepthFormat() const {
+  const Attachment* attachment = GetDepthAttachment();
+  return attachment ? attachment->internal_format() : 0;
+}
+
+GLenum Framebuffer::GetStencilFormat() const {
+  const Attachment* attachment = GetStencilAttachment();
+  return attachment ? attachment->internal_format() : 0;
 }
 
 GLenum Framebuffer::IsPossiblyComplete(const FeatureInfo* feature_info) const {
   if (attachments_.empty()) {
     return GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT;
   }
 
   GLsizei width = -1;
   GLsizei height = -1;
   GLsizei samples = -1;
@@ skipping 354 matching lines @@
 
 bool FramebufferManager::IsComplete(
     Framebuffer* framebuffer) {
   DCHECK(framebuffer);
   return framebuffer->framebuffer_complete_state_count_id() ==
       framebuffer_state_change_count_;
 }
 
 }  // namespace gles2
 }  // namespace gpu