6 files changed, 122 insertions, 1 deletions
diff --git a/cc/proto/BUILD.gn b/cc/proto/BUILD.gn
index f06e869..4387941 100644
--- a/cc/proto/BUILD.gn
+++ b/cc/proto/BUILD.gn
@@ -58,6 +58,7 @@ proto_library("proto_internal") {
     "skregion.proto",
     "skrrect.proto",
     "skxfermode.proto",
+    "synced_property.proto",
     "transform.proto",
     "vector2d.proto",
     "vector2df.proto",
diff --git a/cc/proto/property_tree.proto b/cc/proto/property_tree.proto
index a91824c..d8e8fae 100644
--- a/cc/proto/property_tree.proto
+++ b/cc/proto/property_tree.proto
@@ -7,6 +7,7 @@ syntax = "proto2";
 import "rectf.proto";
 import "scroll_offset.proto";
 import "size.proto";
+import "synced_property.proto";
 import "transform.proto";
 import "vector2df.proto";
 
@@ -156,9 +157,15 @@ message PropertyTree {
   optional ScrollTreeData scroll_tree_data = 1001;
 }
 
+message ScrollOffsetMapEntry {
+  required int64 layer_id = 1;
+  optional SyncedProperty scroll_offset = 2;
+}
+
 // Proto for data members of class ScrollTree
 message ScrollTreeData {
   optional int64 currently_scrolling_node_id = 1;
+  repeated ScrollOffsetMapEntry layer_id_to_scroll_offset_map = 2;
 }
 
 // Proto for data members of class TransformTree.
@@ -174,7 +181,7 @@ message TransformTreeData {
 }
 
 // Proto for class PropertyTrees.
-// NEXT ID: 13
+// NEXT ID: 14
 message PropertyTrees {
   optional PropertyTree transform_tree = 1;
   optional PropertyTree effect_tree = 2;
@@ -186,6 +193,8 @@ message PropertyTrees {
   optional bool changed = 11;
   optional bool full_tree_damaged = 12;
   optional int64 sequence_number = 6;
+  optional bool is_main_thread = 13;
+  optional bool is_active = 14;
 
   optional Vector2dF inner_viewport_container_bounds_delta = 8;
   optional Vector2dF outer_viewport_container_bounds_delta = 9;
diff --git a/cc/proto/synced_property.proto b/cc/proto/synced_property.proto
new file mode 100644
index 0000000..5b8658f
--- /dev/null
+++ b/cc/proto/synced_property.proto
@@ -0,0 +1,29 @@
+// Copyright 2016 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.
+
+syntax = "proto2";
+
+import "scroll_offset.proto";
+
+option optimize_for = LITE_RUNTIME;
+
+package cc.proto;
+
+// Since plumbing SyncedScrollOffset is only used by PropertyTree, and can only
+// travel from main thread to impl thread one way, the From/To protobuf function
+// for SyncedProperty only needs to care the current base, because main thread
+// does not have pending/active tree or scroll offset deltas.
+message ScrollOffsetGroup {
+  optional ScrollOffset pending_base = 1;
+  optional ScrollOffset pending_delta = 2;
+  optional ScrollOffset active_base = 3;
+  optional ScrollOffset active_delta = 4;
+  optional ScrollOffset sent_delta = 5;
+}
+
+message SyncedProperty {
+  optional bool clobber_active_value = 1;
+
+  optional ScrollOffsetGroup scroll_offset_group = 1001;
+}
diff --git a/cc/proto/synced_property_conversions.cc b/cc/proto/synced_property_conversions.cc
new file mode 100644
index 0000000..09c8be2
--- /dev/null
+++ b/cc/proto/synced_property_conversions.cc
@@ -0,0 +1,26 @@
+// Copyright 2016 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 "cc/proto/synced_property_conversions.h"
+
+#include "cc/proto/gfx_conversions.h"
+#include "cc/proto/synced_property.pb.h"
+
+namespace cc {
+
+void SyncedScrollOffsetToProto(const SyncedScrollOffset& synced_scroll_offset,
+                               proto::SyncedProperty* proto) {
+  proto::ScrollOffsetGroup* data = proto->mutable_scroll_offset_group();
+  ScrollOffsetToProto(synced_scroll_offset.PendingBase(),
+                      data->mutable_pending_base());
+}
+
+void ProtoToSyncedScrollOffset(const proto::SyncedProperty& proto,
+                               SyncedScrollOffset* synced_scroll_offset) {
+  const proto::ScrollOffsetGroup& data = proto.scroll_offset_group();
+  synced_scroll_offset->PushFromMainThread(
+      ProtoToScrollOffset(data.pending_base()));
+}
+
+}  // namespace cc
diff --git a/cc/proto/synced_property_conversions.h b/cc/proto/synced_property_conversions.h
new file mode 100644
index 0000000..7f3c623
--- /dev/null
+++ b/cc/proto/synced_property_conversions.h
@@ -0,0 +1,26 @@
+// Copyright 2016 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_PROTO_SYNCED_PROPERTY_CONVERSIONS_H_
+#define CC_PROTO_SYNCED_PROPERTY_CONVERSIONS_H_
+
+#include "cc/base/cc_export.h"
+#include "cc/trees/property_tree.h"
+
+namespace cc {
+
+namespace proto {
+class SyncedProperty;
+}  // namespace proto
+
+CC_EXPORT void SyncedScrollOffsetToProto(
+    const SyncedScrollOffset& synced_scroll_offset,
+    proto::SyncedProperty* proto);
+CC_EXPORT void ProtoToSyncedScrollOffset(
+    const proto::SyncedProperty& proto,
+    SyncedScrollOffset* synced_scroll_offset);
+
+}  // namespace cc
+
+#endif  // CC_PROTO_SYNCED_PROPERTY_CONVERSIONS_H_
diff --git a/cc/proto/synced_property_conversions_unittest.cc b/cc/proto/synced_property_conversions_unittest.cc
new file mode 100644
index 0000000..bf2a4fd
--- /dev/null
+++ b/cc/proto/synced_property_conversions_unittest.cc
@@ -0,0 +1,30 @@
+// Copyright 2016 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 "cc/proto/synced_property_conversions.h"
+
+#include "cc/proto/synced_property.pb.h"
+#include "cc/trees/property_tree.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace cc {
+namespace {
+
+TEST(SyncedPropertyConversionTest, SerializeDeserializeSyncedScrollOffset) {
+  scoped_refptr<SyncedScrollOffset> synced_scroll_offset =
+      new SyncedScrollOffset();
+  synced_scroll_offset->PushFromMainThread(gfx::ScrollOffset(1, 2));
+  proto::SyncedProperty proto;
+  scoped_refptr<SyncedScrollOffset> serialized_synced_scroll_offset =
+      new SyncedScrollOffset();
+  SyncedScrollOffsetToProto(*synced_scroll_offset.get(), &proto);
+  ProtoToSyncedScrollOffset(proto, serialized_synced_scroll_offset.get());
+  EXPECT_EQ(synced_scroll_offset.get()->PendingBase(),
+            serialized_synced_scroll_offset.get()->PendingBase());
+  EXPECT_EQ(synced_scroll_offset.get()->PendingBase(),
+            serialized_synced_scroll_offset.get()->PendingBase());
+}
+
+}  // namespace
+}  // namespace cc