Make scroll offset type of float in cc

cc/trees/layer_tree_host.cc

Index: cc/trees/layer_tree_host.cc
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index eed1e5a7e151e74942e0b78d54b96f38a2f2874d..70c3602ced11deb3e9409dc9e07e09188e19b50c 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -1066,8 +1066,8 @@ void LayerTreeHost::ApplyScrollAndScale(ScrollAndScaleSet* info) {
     QueueSwapPromise(swap_promise.Pass());
   }
 
-  gfx::Vector2d inner_viewport_scroll_delta;
-  gfx::Vector2d outer_viewport_scroll_delta;
+  gfx::ScrollOffset inner_viewport_scroll_delta;

[danakj, 2014/09/25 15:13:31]

these are deltas (relative to an offset) not an offset (relative to origin) from
the name, so why the change?

[Yufeng Shen (Slow to review), 2014/09/25 20:06:24]

Done.

+  gfx::ScrollOffset outer_viewport_scroll_delta;
 
   for (size_t i = 0; i < info->scrolls.size(); ++i) {
     Layer* layer = LayerTreeHostCommon::FindLayerInSubtree(
@@ -1106,10 +1106,13 @@ void LayerTreeHost::ApplyScrollAndScale(ScrollAndScaleSet* info) {
     }
     ApplyPageScaleDeltaFromImplSide(info->page_scale_delta);
 
-    client_->ApplyViewportDeltas(
-        inner_viewport_scroll_delta + outer_viewport_scroll_delta,
-        info->page_scale_delta,
-        info->top_controls_delta);
+    // TODO(miletus): Make viewport delta ScrollOffset.

[danakj, 2014/09/25 15:13:31]

Do you think all deltas should be ScrollOffset type?

[Yufeng Shen (Slow to review), 2014/09/25 20:06:24]

delta changed to be vector2dF to be consistent.

+    gfx::Vector2d viewport_scroll_delta = gfx::ToFlooredVector2d(
+        inner_viewport_scroll_delta + outer_viewport_scroll_delta);
+
+    client_->ApplyViewportDeltas(viewport_scroll_delta,
+                                 info->page_scale_delta,
+                                 info->top_controls_delta);
   }
 }