Add a base class of Texture for interfacing with the mailbox manager.

gpu/command_buffer/service/mailbox_manager_impl.cc

Index: gpu/command_buffer/service/mailbox_manager_impl.cc
diff --git a/gpu/command_buffer/service/mailbox_manager_impl.cc b/gpu/command_buffer/service/mailbox_manager_impl.cc
index a8ce6eda49f8c5a03c01ed97d6f0efd1cb6ab565..a1df7f1d2acb8d40111a2e0501d0920338d5f9bf 100644
--- a/gpu/command_buffer/service/mailbox_manager_impl.cc
+++ b/gpu/command_buffer/service/mailbox_manager_impl.cc
@@ -25,7 +25,7 @@ bool MailboxManagerImpl::UsesSync() {
   return false;
 }
 
-Texture* MailboxManagerImpl::ConsumeTexture(const Mailbox& mailbox) {
+TextureBase* MailboxManagerImpl::ConsumeTexture(const Mailbox& mailbox) {
   MailboxToTextureMap::iterator it =
       mailbox_to_textures_.find(mailbox);
   if (it != mailbox_to_textures_.end())
@@ -35,7 +35,7 @@ Texture* MailboxManagerImpl::ConsumeTexture(const Mailbox& mailbox) {
 }
 
 void MailboxManagerImpl::ProduceTexture(const Mailbox& mailbox,
-                                        Texture* texture) {
+                                        TextureBase* texture) {
   MailboxToTextureMap::iterator it = mailbox_to_textures_.find(mailbox);
   if (it != mailbox_to_textures_.end()) {
     if (it->second->first == texture)
@@ -49,7 +49,7 @@ void MailboxManagerImpl::ProduceTexture(const Mailbox& mailbox,
 }
 
 void MailboxManagerImpl::InsertTexture(const Mailbox& mailbox,
-                                       Texture* texture) {
+                                       TextureBase* texture) {
   texture->SetMailboxManager(this);
   TextureToMailboxMap::iterator texture_it =
       textures_to_mailboxes_.insert(std::make_pair(texture, mailbox));
@@ -57,7 +57,7 @@ void MailboxManagerImpl::InsertTexture(const Mailbox& mailbox,
   DCHECK_EQ(mailbox_to_textures_.size(), textures_to_mailboxes_.size());
 }
 
-void MailboxManagerImpl::TextureDeleted(Texture* texture) {
+void MailboxManagerImpl::TextureDeleted(TextureBase* texture) {
   std::pair<TextureToMailboxMap::iterator,
             TextureToMailboxMap::iterator> range =
       textures_to_mailboxes_.equal_range(texture);