[Android] Disable pull-to-refresh with overflow-y:hidden

Currently, the only way to disable the pull-to-refresh effect is to
explictly preventDefault the causal touches or suppress their default
actions with touch-action: none. However, the latter prevents
any kind of accelerated scrolling, and the former can be to get right
with composed or nested scrollable content.

Use the overflow-y:hidden property on the root element as a signal to
disable the effect. This dovetails with how this property both prevents
hiding of the top controls and suppresses the overscroll glow effect.

BUG=456515,456300

Review URL: https://codereview.chromium.org/910373002

Cr-Commit-Position: refs/heads/master@{#315938}

1 files changed, 10 insertions, 0 deletions

diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index bd77d84..95e1ab1 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -1458,6 +1458,16 @@ CompositorFrameMetadata LayerTreeHostImpl::MakeCompositorFrameMetadata() const {
   active_tree_->GetViewportSelection(&metadata.selection_start,
                                      &metadata.selection_end);
 
+  LayerImpl* root_layer_for_overflow = OuterViewportScrollLayer()
+                                           ? OuterViewportScrollLayer()
+                                           : InnerViewportScrollLayer();
+  if (root_layer_for_overflow) {
+    metadata.root_overflow_x_hidden =
+        !root_layer_for_overflow->user_scrollable_horizontal();
+    metadata.root_overflow_y_hidden =
+        !root_layer_for_overflow->user_scrollable_vertical();
+  }
+
   if (!InnerViewportScrollLayer())
     return metadata;