Mozart: Improve tracing and backpressure.

services/gfx/compositor/graph/snapshot.h

 // 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.
 
 #ifndef SERVICES_GFX_COMPOSITOR_GRAPH_SNAPSHOT_H_
 #define SERVICES_GFX_COMPOSITOR_GRAPH_SNAPSHOT_H_
 
 #include <iosfwd>
 #include <unordered_map>
 #include <unordered_set>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "mojo/services/geometry/interfaces/geometry.mojom.h"
 #include "mojo/services/gfx/composition/interfaces/hit_tests.mojom.h"
 #include "mojo/services/gfx/composition/interfaces/scheduling.mojom.h"
+#include "services/gfx/compositor/render/render_frame.h"
 
 namespace compositor {
 
 class Node;
 class SceneContent;
 class SceneNode;
-class RenderFrame;
 
 // Describes a single frame snapshot of the scene graph, sufficient for
 // rendering and hit testing.  When the snapshot is made, all predicated and
 // blocked scene nodes are evaluated to produce a final description of
 // the content of the frame along with its dependencies.
 //
 // The snapshot holds a list of dependencies for the scenes whose state was
 // originally used to produce it so that the snapshot can be invalidated
 // whenever one of these scenes changes.  Note that the snapshot will contain
 // a list of dependencies even when rendering is blocked, in which case
@@ skipping 22 matching lines @@
   // Gets the root scene content for the snapshot, or null if blocked.
   const SceneContent* root_scene_content() const {
     return root_scene_content_.get();
   }
 
   // Returns true if the snapshot has a dependency on content from the
   // specified scene.
   bool HasDependency(
       const mojo::gfx::composition::SceneToken& scene_token) const;
 
-  // Creates a frame for rendering.
+  // Paints the content of the snapshot to produce a frame to be rendered.
   // Only valid if |!is_blocked()|.
-  scoped_refptr<RenderFrame> CreateFrame(
-      const mojo::Rect& viewport,
-      const mojo::gfx::composition::FrameInfo& frame_info) const;
+  scoped_refptr<RenderFrame> Paint(const RenderFrame::Metadata& metadata,
+                                   const mojo::Rect& viewport) const;
 
   // Performs a hit test at the specified point, populating the result.
   // Only valid if |!is_blocked()|.
   void HitTest(const mojo::PointF& point,
                mojo::gfx::composition::HitTestResult* result) const;
 
   // Returns true if the specified node was blocked from rendering.
   // Only valid if |!is_blocked()|.
   bool IsNodeBlocked(const Node* node) const;
 
@@ skipping 77 matching lines @@
 
   scoped_refptr<Snapshot> snapshot_;
   std::ostream* const block_log_;
 
   DISALLOW_COPY_AND_ASSIGN(SnapshotBuilder);
 };
 
 }  // namespace compositor
 
 #endif  // SERVICES_GFX_COMPOSITOR_GRAPH_SNAPSHOT_H_