Implement TextureImageTransportSurface using texture mailbox

gpu/command_buffer/service/mailbox_manager.cc

Index: gpu/command_buffer/service/mailbox_manager.cc
diff --git a/gpu/command_buffer/service/mailbox_manager.cc b/gpu/command_buffer/service/mailbox_manager.cc
index ec7ad948bb273d61ff2e7bfc0d94448dbefcb041..188e683b8d35c9a1d53a4df4b44db383dd325c71 100644
--- a/gpu/command_buffer/service/mailbox_manager.cc
+++ b/gpu/command_buffer/service/mailbox_manager.cc
@@ -22,6 +22,7 @@ MailboxManager::MailboxManager()
 }
 
 MailboxManager::~MailboxManager() {
+  DCHECK(!textures_.size());
 }
 
 void MailboxManager::GenerateMailboxName(MailboxName* name) {
@@ -36,10 +37,8 @@ TextureDefinition* MailboxManager::ConsumeTexture(unsigned target,
 
   TextureDefinitionMap::iterator it =
       textures_.find(TargetName(target, name));
-  if (it == textures_.end()) {
-    NOTREACHED();
+  if (it == textures_.end())
     return NULL;
-  }
 
   TextureDefinition* definition = it->second.definition.release();
   textures_.erase(it);