Unbind video texture from mailbox after copying to WebGL.

gpu/command_buffer/service/mailbox_manager_impl.cc

 // Copyright 2014 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/mailbox_manager_impl.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
@@ skipping 26 matching lines @@
 void MailboxManagerImpl::ProduceTexture(const Mailbox& mailbox,
                                         Texture* texture) {
   MailboxToTextureMap::iterator it = mailbox_to_textures_.find(mailbox);
   if (it != mailbox_to_textures_.end()) {
     if (it->second->first == texture)
       return;
     TextureToMailboxMap::iterator texture_it = it->second;
     mailbox_to_textures_.erase(it);
     textures_to_mailboxes_.erase(texture_it);
   }
-  InsertTexture(mailbox, texture);
+  if (texture)
+    InsertTexture(mailbox, texture);
 }
 
 void MailboxManagerImpl::InsertTexture(const Mailbox& mailbox,
                                        Texture* texture) {
   texture->SetMailboxManager(this);
   TextureToMailboxMap::iterator texture_it =
       textures_to_mailboxes_.insert(std::make_pair(texture, mailbox));
   mailbox_to_textures_.insert(std::make_pair(mailbox, texture_it));
   DCHECK_EQ(mailbox_to_textures_.size(), textures_to_mailboxes_.size());
 }
 
 void MailboxManagerImpl::TextureDeleted(Texture* texture) {
   std::pair<TextureToMailboxMap::iterator,
             TextureToMailboxMap::iterator> range =
       textures_to_mailboxes_.equal_range(texture);
   for (TextureToMailboxMap::iterator it = range.first;
        it != range.second; ++it) {
     size_t count = mailbox_to_textures_.erase(it->second);
     DCHECK(count == 1);
   }
   textures_to_mailboxes_.erase(range.first, range.second);
   DCHECK_EQ(mailbox_to_textures_.size(), textures_to_mailboxes_.size());
 }
 
 }  // namespace gles2
 }  // namespace gpu