Added serialization to protobufs for property trees.

cc/trees/property_tree.h

 // Copyright 2014 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 CC_TREES_PROPERTY_TREE_H_
 #define CC_TREES_PROPERTY_TREE_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "cc/base/cc_export.h"
 #include "ui/gfx/geometry/rect_f.h"
 #include "ui/gfx/geometry/scroll_offset.h"
 #include "ui/gfx/transform.h"
 
 namespace cc {
 
+namespace proto {
+class ClipNodeData;
+class EffectNodeData;
+class PropertyTree;
+class PropertyTrees;
+class TranformNodeData;
+class TransformTreeData;
+class TreeNode;
+}
+
+// Each class declared here has a corresponding proto defined in
+// cc/proto/property_tree.proto. When making any changes to a class structure
+// including addition/deletion/updation of a field, please also make the
+// change to its proto and the ToProtobuf and FromProtobuf methods for that
+// class.
+
 template <typename T>
 struct CC_EXPORT TreeNode {
   TreeNode() : id(-1), parent_id(-1), owner_id(-1), data() {}
   int id;
   int parent_id;
   int owner_id;
   T data;
+
+  void ToProtobuf(proto::TreeNode* proto) const;
+  void FromProtobuf(const proto::TreeNode& proto);
 };
 
 struct CC_EXPORT TransformNodeData {
   TransformNodeData();
   ~TransformNodeData();
 
   // The local transform information is combined to form to_parent (ignoring
   // snapping) as follows:
   //
   //   to_parent = M_post_local * T_scroll * M_local * M_pre_local.
@@ skipping 108 matching lines @@
 
   void set_to_parent(const gfx::Transform& transform) {
     to_parent = transform;
     is_invertible = to_parent.IsInvertible();
   }
 
   void update_pre_local_transform(const gfx::Point3F& transform_origin);
 
   void update_post_local_transform(const gfx::PointF& position,
                                    const gfx::Point3F& transform_origin);
+
+  void ToProtobuf(proto::TreeNode* proto) const;
+  void FromProtobuf(const proto::TreeNode& proto);
 };
 
 typedef TreeNode<TransformNodeData> TransformNode;
 
 struct CC_EXPORT ClipNodeData {
   ClipNodeData();
 
   // The clip rect that this node contributes, expressed in the space of its
   // transform node.
   gfx::RectF clip;
@@ skipping 28 matching lines @@
   // True if target surface needs to be drawn with a clip applied.
   bool target_is_clipped : 1;
 
   // True if layers with this clip tree node need to be drawn with a clip
   // applied.
   bool layers_are_clipped : 1;
   bool layers_are_clipped_when_surfaces_disabled : 1;
 
   // Nodes that correspond to unclipped surfaces disregard ancestor clips.
   bool resets_clip : 1;
+
+  bool operator==(const ClipNodeData& other) const;
+
+  void ToProtobuf(proto::TreeNode* proto) const;
+  void FromProtobuf(const proto::TreeNode& proto);
 };
 
 typedef TreeNode<ClipNodeData> ClipNode;
 
 struct CC_EXPORT EffectNodeData {
   EffectNodeData();
 
   float opacity;
   float screen_space_opacity;
 
   bool has_render_surface;
   int transform_id;
   int clip_id;
+
+  bool operator==(const EffectNodeData& other) const;
+
+  void ToProtobuf(proto::TreeNode* proto) const;
+  void FromProtobuf(const proto::TreeNode& proto);
 };
 
 typedef TreeNode<EffectNodeData> EffectNode;
 
 template <typename T>
 class CC_EXPORT PropertyTree {
  public:
   PropertyTree();
   virtual ~PropertyTree();
 
@@ skipping 19 matching lines @@
   }
 
   virtual void clear();
   size_t size() const { return nodes_.size(); }
 
   void set_needs_update(bool needs_update) { needs_update_ = needs_update; }
   bool needs_update() const { return needs_update_; }
 
   int next_available_id() const { return static_cast<int>(size()); }
 
+  void ToProtobuf(proto::PropertyTree* proto) const;
+  void FromProtobuf(const proto::PropertyTree& proto);
+
  private:
   // Copy and assign are permitted. This is how we do tree sync.
   std::vector<T> nodes_;
 
   bool needs_update_;
 };
 
 class CC_EXPORT TransformTree final : public PropertyTree<TransformNode> {
  public:
   TransformTree();
@@ skipping 78 matching lines @@
   gfx::Vector2dF outer_viewport_bounds_delta() const {
     return outer_viewport_bounds_delta_;
   }
 
   void AddNodeAffectedByInnerViewportBoundsDelta(int node_id);
   void AddNodeAffectedByOuterViewportBoundsDelta(int node_id);
 
   bool HasNodesAffectedByInnerViewportBoundsDelta() const;
   bool HasNodesAffectedByOuterViewportBoundsDelta() const;
 
+  void ToProtobuf(proto::PropertyTree* proto) const;
+  void FromProtobuf(const proto::PropertyTree& proto);
+
  private:
   // Returns true iff the node at |desc_id| is a descendant of the node at
   // |anc_id|.
   bool IsDescendant(int desc_id, int anc_id) const;
 
   // Computes the combined transform between |source_id| and |dest_id| and
   // returns false if the inverse of a singular transform was used. These two
   // nodes must be on the same ancestor chain.
   bool CombineTransformsBetween(int source_id,
                                 int dest_id,
@@ skipping 32 matching lines @@
   gfx::Vector2dF inner_viewport_bounds_delta_;
   gfx::Vector2dF outer_viewport_bounds_delta_;
   std::vector<int> nodes_affected_by_inner_viewport_bounds_delta_;
   std::vector<int> nodes_affected_by_outer_viewport_bounds_delta_;
 };
 
 class CC_EXPORT ClipTree final : public PropertyTree<ClipNode> {
  public:
   void SetViewportClip(gfx::RectF viewport_rect);
   gfx::RectF ViewportClip();
+
+  void ToProtobuf(proto::PropertyTree* proto) const;
+  void FromProtobuf(const proto::PropertyTree& proto);
 };
 
 class CC_EXPORT EffectTree final : public PropertyTree<EffectNode> {
  public:
   void UpdateOpacities(int id);
+
+  void ToProtobuf(proto::PropertyTree* proto) const;
+  void FromProtobuf(const proto::PropertyTree& proto);
 };
 
 class CC_EXPORT PropertyTrees final {
  public:
   PropertyTrees();
 
+  static PropertyTrees CreateFromProtobuf(const proto::PropertyTrees& proto);

[David Trainor- moved to gerrit, 2015/11/12 22:46:11]

do we want to just return a PropertyTrees object here?  What's the overhead of
doing this?  I don't know enough about whether or not the compiler can be smart
in these cases.

[Khushal, 2015/11/13 10:33:13]

Yeah, just returning property trees is bad. I added it as a method to property
trees. This way when we de-serialize the layer tree host for a commit, we can
just de-serialize into the property trees in the LTH.

+  void ToProtobuf(proto::PropertyTrees* proto) const;
+
   TransformTree transform_tree;
   EffectTree effect_tree;
   ClipTree clip_tree;
   bool needs_rebuild;
   bool non_root_surfaces_enabled;
   int sequence_number;
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_PROPERTY_TREE_H_