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

gpu/command_buffer/service/framebuffer_manager.h

 // 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.
 
 #ifndef GPU_COMMAND_BUFFER_SERVICE_FRAMEBUFFER_MANAGER_H_
 #define GPU_COMMAND_BUFFER_SERVICE_FRAMEBUFFER_MANAGER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 133 matching lines @@
     has_been_bound_ = true;
   }
 
   bool IsValid() const {
     return has_been_bound_ && !IsDeleted();
   }
 
   bool HasColorAttachment(int index) const;
   bool HasDepthAttachment() const;
   bool HasStencilAttachment() const;
+  // The following look at DEPTH_STENCIL_ATTACHMENT or
+  // DEPTH_ATTACHMENT/STENCIL_ATTACHMENT.
+  // TODO(piman): DEPTH_STENCIL_ATTACHMENT is not a real attachment point,
+  // except for WebGL1. Fix this.  http://crbug.com/630568
+  const Attachment* GetDepthAttachment() const;
+  const Attachment* GetStencilAttachment() const;
   GLenum GetDepthFormat() const;
   GLenum GetStencilFormat() const;
   GLenum GetDrawBufferInternalFormat() const;
   GLenum GetReadBufferInternalFormat() const;
   // If the color attachment is a texture, returns its type; otherwise,
   // returns 0.
   GLenum GetReadBufferTextureType() const;
 
   // Verify all the rules in OpenGL ES 2.0.25 4.4.5 are followed.
   // Returns GL_FRAMEBUFFER_COMPLETE if there are no reasons we know we can't
@@ skipping 215 matching lines @@
 
   scoped_refptr<FramebufferCompletenessCache> framebuffer_combo_complete_cache_;
 
   DISALLOW_COPY_AND_ASSIGN(FramebufferManager);
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_FRAMEBUFFER_MANAGER_H_