Stop non-user scrollable layers from scrolling on the compositor

BUG=579207
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1623663002

Cr-Commit-Position: refs/heads/master@{#371250}
(cherry picked from commit 399b4764c4020e5a0c2e4da0f457971447f6b286)

Review URL: https://codereview.chromium.org/1633253002 .

Cr-Commit-Position: refs/branch-heads/2623@{#146}
Cr-Branched-From: 92d77538a86529ca35f9220bd3cd512cbea1f086-refs/heads/master@{#369907}

2 files changed, 94 insertions, 4 deletions

diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index 057228f..96c1d68 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -2632,7 +2632,12 @@ InputHandler::ScrollStatus LayerTreeHostImpl::ScrollAnimated(
     const gfx::Point& viewport_point,
     const gfx::Vector2dF& scroll_delta) {
   if (LayerImpl* layer_impl = CurrentlyScrollingLayer()) {
-    return ScrollAnimationUpdateTarget(layer_impl, scroll_delta)
+    gfx::Vector2dF delta = scroll_delta;
+    if (!layer_impl->user_scrollable(ScrollbarOrientation::HORIZONTAL))
+      delta.set_x(0);
+    if (!layer_impl->user_scrollable(ScrollbarOrientation::VERTICAL))
+      delta.set_y(0);
+    return ScrollAnimationUpdateTarget(layer_impl, delta)
                ? SCROLL_STARTED
                : SCROLL_IGNORED;
   }
@@ -2659,6 +2664,15 @@ InputHandler::ScrollStatus LayerTreeHostImpl::ScrollAnimated(
       target_offset.SetToMin(layer_impl->MaxScrollOffset());
       gfx::Vector2dF actual_delta = target_offset.DeltaFrom(current_offset);
 
+      if (!layer_impl->user_scrollable(ScrollbarOrientation::HORIZONTAL)) {
+        actual_delta.set_x(0);
+        target_offset.set_x(current_offset.x());
+      }
+      if (!layer_impl->user_scrollable(ScrollbarOrientation::VERTICAL)) {
+        actual_delta.set_y(0);
+        target_offset.set_y(current_offset.y());
+      }
+
       const float kEpsilon = 0.1f;
       bool can_layer_scroll = (std::abs(actual_delta.x()) > kEpsilon ||
                                std::abs(actual_delta.y()) > kEpsilon);
diff --git a/cc/trees/layer_tree_host_impl_unittest.cc b/cc/trees/layer_tree_host_impl_unittest.cc
index 814279e..e3e1f53 100644
--- a/cc/trees/layer_tree_host_impl_unittest.cc
+++ b/cc/trees/layer_tree_host_impl_unittest.cc
@@ -9143,7 +9143,10 @@ TEST_F(LayerTreeHostImplTest, ScrollAnimated) {
 // Test that a smooth scroll offset animation is aborted when followed by a
 // non-smooth scroll offset animation.
 TEST_F(LayerTreeHostImplTimelinesTest, ScrollAnimatedAborted) {
-  SetupScrollAndContentsLayers(gfx::Size(100, 200));
+  const gfx::Size content_size(1000, 1000);
+  const gfx::Size viewport_size(500, 500);
+  CreateBasicVirtualViewportLayers(viewport_size, content_size);
+
   DrawFrame();
 
   base::TimeTicks start_time =
@@ -9208,7 +9211,10 @@ TEST_F(LayerTreeHostImplTimelinesTest, ScrollAnimatedAborted) {
 
 // Evolved from LayerTreeHostImplTest.ScrollAnimated.
 TEST_F(LayerTreeHostImplTimelinesTest, ScrollAnimated) {
-  SetupScrollAndContentsLayers(gfx::Size(100, 200));
+  const gfx::Size content_size(1000, 1000);
+  const gfx::Size viewport_size(500, 500);
+  CreateBasicVirtualViewportLayers(viewport_size, content_size);
+
   DrawFrame();
 
   base::TimeTicks start_time =
@@ -9221,7 +9227,6 @@ TEST_F(LayerTreeHostImplTimelinesTest, ScrollAnimated) {
             host_impl_->ScrollAnimated(gfx::Point(), gfx::Vector2d(0, 50)));
 
   LayerImpl* scrolling_layer = host_impl_->CurrentlyScrollingLayer();
-
   begin_frame_args.frame_time = start_time;
   host_impl_->WillBeginImplFrame(begin_frame_args);
   host_impl_->Animate();
@@ -9267,6 +9272,77 @@ TEST_F(LayerTreeHostImplTimelinesTest, ScrollAnimated) {
   host_impl_->DidFinishImplFrame();
 }
 
+// Test that smooth scroll offset animation doesn't happen for non user
+// scrollable layers.
+TEST_F(LayerTreeHostImplTimelinesTest, ScrollAnimatedNotUserScrollable) {
+  const gfx::Size content_size(1000, 1000);
+  const gfx::Size viewport_size(500, 500);
+  CreateBasicVirtualViewportLayers(viewport_size, content_size);
+
+  host_impl_->OuterViewportScrollLayer()->set_user_scrollable_vertical(true);
+  host_impl_->OuterViewportScrollLayer()->set_user_scrollable_horizontal(false);
+
+  DrawFrame();
+
+  base::TimeTicks start_time =
+      base::TimeTicks() + base::TimeDelta::FromMilliseconds(100);
+
+  BeginFrameArgs begin_frame_args =
+      CreateBeginFrameArgsForTesting(BEGINFRAME_FROM_HERE);
+
+  EXPECT_EQ(
+      InputHandler::SCROLL_STARTED,
+      host_impl_->ScrollAnimated(gfx::Point(), gfx::Vector2d(50, 50)));
+
+  LayerImpl* scrolling_layer = host_impl_->CurrentlyScrollingLayer();
+  begin_frame_args.frame_time = start_time;
+  host_impl_->WillBeginImplFrame(begin_frame_args);
+  host_impl_->Animate();
+  host_impl_->UpdateAnimationState(true);
+
+  EXPECT_EQ(gfx::ScrollOffset(), scrolling_layer->CurrentScrollOffset());
+  host_impl_->DidFinishImplFrame();
+
+  begin_frame_args.frame_time =
+      start_time + base::TimeDelta::FromMilliseconds(50);
+  host_impl_->WillBeginImplFrame(begin_frame_args);
+  host_impl_->Animate();
+  host_impl_->UpdateAnimationState(true);
+
+  // Should not have scrolled horizontally.
+  EXPECT_EQ(0, scrolling_layer->CurrentScrollOffset().x());
+  float y = scrolling_layer->CurrentScrollOffset().y();
+  EXPECT_TRUE(y > 1 && y < 49);
+
+  // Update target.
+  EXPECT_EQ(
+      InputHandler::SCROLL_STARTED,
+      host_impl_->ScrollAnimated(gfx::Point(), gfx::Vector2d(50, 50)));
+  host_impl_->DidFinishImplFrame();
+
+  begin_frame_args.frame_time =
+      start_time + base::TimeDelta::FromMilliseconds(200);
+  host_impl_->WillBeginImplFrame(begin_frame_args);
+  host_impl_->Animate();
+  host_impl_->UpdateAnimationState(true);
+
+  y = scrolling_layer->CurrentScrollOffset().y();
+  EXPECT_TRUE(y > 50 && y < 100);
+  EXPECT_EQ(scrolling_layer, host_impl_->CurrentlyScrollingLayer());
+  host_impl_->DidFinishImplFrame();
+
+  begin_frame_args.frame_time =
+      start_time + base::TimeDelta::FromMilliseconds(250);
+  host_impl_->WillBeginImplFrame(begin_frame_args);
+  host_impl_->Animate();
+  host_impl_->UpdateAnimationState(true);
+
+  EXPECT_VECTOR_EQ(gfx::ScrollOffset(0, 100),
+                   scrolling_layer->CurrentScrollOffset());
+  EXPECT_EQ(NULL, host_impl_->CurrentlyScrollingLayer());
+  host_impl_->DidFinishImplFrame();
+}
+
 TEST_F(LayerTreeHostImplTest, InvalidLayerNotAddedToRasterQueue) {
   host_impl_->CreatePendingTree();