cc: Make TransformNodeData scroll offset a ScrollOffset

Rather than converting everywhere from ScrollOffset to Vector2dF,
instead just store the scroll offset directly.

R=ajuma@chromium.org,vollick@chromium.org

Review URL: https://codereview.chromium.org/1142853003

Cr-Commit-Position: refs/heads/master@{#330533}

cc/layers/layer.cc

@@ -811,8 +811,7 @@ void Layer::SetScrollOffset(const gfx::ScrollOffset& scroll_offset) {
           layer_tree_host_->property_trees()->transform_tree.Node(
               transform_tree_index())) {
     if (transform_node->owner_id == id()) {
-      transform_node->data.scroll_offset =
-          gfx::ScrollOffsetToVector2dF(CurrentScrollOffset());
+      transform_node->data.scroll_offset = CurrentScrollOffset();
       transform_node->data.needs_local_transform_update = true;
       layer_tree_host_->property_trees()->transform_tree.set_needs_update(true);
       SetNeedsCommitNoRebuild();
@@ -851,8 +850,7 @@ void Layer::SetScrollOffsetFromImplSide(
           layer_tree_host_->property_trees()->transform_tree.Node(
               transform_tree_index())) {
     if (transform_node->owner_id == id()) {
-      transform_node->data.scroll_offset =
-          gfx::ScrollOffsetToVector2dF(CurrentScrollOffset());
+      transform_node->data.scroll_offset = CurrentScrollOffset();
       transform_node->data.needs_local_transform_update = true;
       layer_tree_host_->property_trees()->transform_tree.set_needs_update(true);
       needs_rebuild = false;

cc/trees/property_tree.h

@@ -10,6 +10,7 @@
 #include "base/basictypes.h"
 #include "cc/base/cc_export.h"
 #include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/geometry/scroll_offset.h"
 #include "ui/gfx/transform.h"
 
 namespace cc {
@@ -96,7 +97,7 @@ struct CC_EXPORT TransformNodeData {
   gfx::Vector2dF sublayer_scale;
 
   // TODO(vollick): will be moved when accelerated effects are implemented.
-  gfx::Vector2dF scroll_offset;
+  gfx::ScrollOffset scroll_offset;
 
   // We scroll snap where possible, but this has an effect on scroll
   // compensation: the snap is yet more scrolling that must be compensated for.

cc/trees/property_tree_builder.cc

@@ -282,10 +282,8 @@ bool AddTransformNodeIfNeeded(
                                            layer->transform_origin());
   }
 
-  if (!layer->scroll_parent()) {
-    node->data.scroll_offset =
-        gfx::ScrollOffsetToVector2dF(layer->CurrentScrollOffset());
-  }
+  if (!layer->scroll_parent())
+    node->data.scroll_offset = layer->CurrentScrollOffset();
 
   node->data.local = layer->transform();
   node->data.update_pre_local_transform(layer->transform_origin());