Update from chromium https://crrev.com/301315

gpu/command_buffer/service/mailbox_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/mailbox_manager.h"
-
-#include <algorithm>
-
-#include "crypto/random.h"
-#include "gpu/command_buffer/service/mailbox_synchronizer.h"
-#include "gpu/command_buffer/service/texture_manager.h"
-
-namespace gpu {
-namespace gles2 {
-
-MailboxManager::MailboxManager()
-    : mailbox_to_textures_(std::ptr_fun(&MailboxManager::TargetNameLess)),
-      sync_(MailboxSynchronizer::GetInstance()) {
-}
-
-MailboxManager::~MailboxManager() {
-  DCHECK(mailbox_to_textures_.empty());
-  DCHECK(textures_to_mailboxes_.empty());
-}
-
-Texture* MailboxManager::ConsumeTexture(unsigned target,
-                                        const Mailbox& mailbox) {
-  TargetName target_name(target, mailbox);
-  MailboxToTextureMap::iterator it =
-      mailbox_to_textures_.find(target_name);
-  if (it != mailbox_to_textures_.end())
-    return it->second->first;
-
-  if (sync_) {
-    // See if it's visible in another mailbox manager, and if so make it visible
-    // here too.
-    Texture* texture = sync_->CreateTextureFromMailbox(target, mailbox);
-    if (texture) {
-      InsertTexture(target_name, texture);
-      DCHECK_EQ(0U, texture->refs_.size());
-    }
-    return texture;
-  }
-
-  return NULL;
-}
-
-void MailboxManager::ProduceTexture(unsigned target,
-                                    const Mailbox& mailbox,
-                                    Texture* texture) {
-  TargetName target_name(target, mailbox);
-  MailboxToTextureMap::iterator it = mailbox_to_textures_.find(target_name);
-  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(target_name, texture);
-}
-
-void MailboxManager::InsertTexture(TargetName target_name, Texture* texture) {
-  texture->SetMailboxManager(this);
-  TextureToMailboxMap::iterator texture_it =
-      textures_to_mailboxes_.insert(std::make_pair(texture, target_name));
-  mailbox_to_textures_.insert(std::make_pair(target_name, texture_it));
-  DCHECK_EQ(mailbox_to_textures_.size(), textures_to_mailboxes_.size());
-}
-
-void MailboxManager::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());
-
-  if (sync_)
-    sync_->TextureDeleted(texture);
-}
-
-void MailboxManager::PushTextureUpdates(uint32 sync_point) {
-  if (sync_)
-    sync_->PushTextureUpdates(this, sync_point);
-}
-
-void MailboxManager::PullTextureUpdates(uint32 sync_point) {
-  if (sync_)
-    sync_->PullTextureUpdates(this, sync_point);
-}
-
-MailboxManager::TargetName::TargetName(unsigned target, const Mailbox& mailbox)
-    : target(target),
-      mailbox(mailbox) {
-}
-
-bool MailboxManager::TargetNameLess(const MailboxManager::TargetName& lhs,
-                                    const MailboxManager::TargetName& rhs) {
-  if (lhs.target != rhs.target)
-    return lhs.target < rhs.target;
-  return lhs.mailbox < rhs.mailbox;
-}
-
-}  // namespace gles2
-}  // namespace gpu