Mozart: Make Snapshot immutable.

services/gfx/compositor/renderer_state.cc

 // Copyright 2015 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 "services/gfx/compositor/renderer_state.h"
 
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
 
 namespace compositor {
@@ skipping 21 matching lines @@
 
 bool RendererState::ResetRootScene() {
   if (root_scene_) {
     root_scene_ = nullptr;
     SetSnapshot(nullptr);
     return true;
   }
   return false;
 }
 
-bool RendererState::SetSnapshot(std::unique_ptr<Snapshot> snapshot) {
-  snapshot_ = std::move(snapshot);
-  if (snapshot_ && snapshot_->valid()) {
-    frame_ = snapshot_->frame();
-    DCHECK(frame_);
-    return true;
-  }
-  return false;
+void RendererState::SetSnapshot(const scoped_refptr<const Snapshot>& snapshot) {
+  current_snapshot_ = snapshot;
+  if (current_snapshot_ && !current_snapshot_->is_blocked())
+    visible_snapshot_ = current_snapshot_;
 }
 
 std::string RendererState::FormattedLabel() {
   if (formatted_label_cache_.empty()) {
     formatted_label_cache_ =
         label_.empty() ? base::StringPrintf("<%d>", id_)
                        : base::StringPrintf("<%d:%s>", id_, label_.c_str());
   }
   return formatted_label_cache_;
 }
 
 std::ostream& operator<<(std::ostream& os, RendererState* renderer_state) {
   if (!renderer_state)
     return os << "null";
   return os << renderer_state->FormattedLabel();
 }
 
 }  // namespace compositor