Allow immutable textures into mailboxes

gpu/command_buffer/service/texture_manager.cc

Index: gpu/command_buffer/service/texture_manager.cc
diff --git a/gpu/command_buffer/service/texture_manager.cc b/gpu/command_buffer/service/texture_manager.cc
index 3c30519e9ff9134fc22326279883322d6ff449cb..aa786680bd78e103315c01df0b1ef9751d96427c 100644
--- a/gpu/command_buffer/service/texture_manager.cc
+++ b/gpu/command_buffer/service/texture_manager.cc
@@ -861,9 +861,6 @@ TextureDefinition* TextureManager::Save(TextureInfo* info) {
   if (info->IsAttachedToFramebuffer())
     return NULL;
 
-  if (info->IsImmutable())
-    return NULL;
-
   TextureDefinition::LevelInfos level_infos(info->level_infos_.size());
   for (size_t face = 0; face < level_infos.size(); ++face) {
     GLenum target = info->target() == GL_TEXTURE_2D ?
@@ -897,13 +894,16 @@ TextureDefinition* TextureManager::Save(TextureInfo* info) {
   }
 
   GLuint old_service_id = info->service_id();
+  bool immutable = info->IsImmutable();
 
   GLuint new_service_id = 0;
   glGenTextures(1, &new_service_id);
   info->SetServiceId(new_service_id);
+  info->SetImmutable(false);
 
   return new TextureDefinition(info->target(),
                                old_service_id,
+                               immutable,
                                level_infos);
 }
 
@@ -916,9 +916,6 @@ bool TextureManager::Restore(TextureInfo* info,
   if (info->IsAttachedToFramebuffer())
     return false;
 
-  if (info->IsImmutable())
-    return false;
-
   if (info->target() != definition->target())
     return false;
 
@@ -951,6 +948,7 @@ bool TextureManager::Restore(TextureInfo* info,
   GLuint old_service_id = info->service_id();
   glDeleteTextures(1, &old_service_id);
   info->SetServiceId(definition->ReleaseServiceId());
+  info->SetImmutable(definition->immutable());
 
   return true;
 }