Communicate MT changes to impl-only scroll offset animations

third_party/WebKit/Source/platform/scroll/ScrollAnimatorCompositorCoordinator.cpp

Index: third_party/WebKit/Source/platform/scroll/ScrollAnimatorCompositorCoordinator.cpp
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollAnimatorCompositorCoordinator.cpp b/third_party/WebKit/Source/platform/scroll/ScrollAnimatorCompositorCoordinator.cpp
index 41858117597c83e260d30c92e1c10d6dba15207d..7ba39fab8a8fdfb1bb4740b83066fa1a81d64fe8 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollAnimatorCompositorCoordinator.cpp
+++ b/third_party/WebKit/Source/platform/scroll/ScrollAnimatorCompositorCoordinator.cpp
@@ -6,6 +6,7 @@
 
 #include "cc/animation/scroll_offset_animation_curve.h"
 #include "platform/RuntimeEnabledFeatures.h"
+#include "platform/animation/CompositorAnimationHost.h"
 #include "platform/animation/CompositorAnimationPlayer.h"
 #include "platform/animation/CompositorAnimationTimeline.h"
 #include "platform/graphics/CompositorFactory.h"
@@ -47,6 +48,9 @@ void ScrollAnimatorCompositorCoordinator::resetAnimationState()
 
 bool ScrollAnimatorCompositorCoordinator::hasAnimationThatRequiresService() const
 {
+    if (!m_implOnlyAnimationUpdates.empty()) {
+        return true;
+    }
     switch (m_runState) {
     case RunState::Idle:
     case RunState::RunningOnCompositor:
@@ -238,6 +242,40 @@ FloatPoint ScrollAnimatorCompositorCoordinator::blinkOffsetFromCompositorOffset(
     return offset;
 }
 
+void ScrollAnimatorCompositorCoordinator::updateCompositorAnimations()
+{
+    if (!getScrollableArea()->scrollAnimatorEnabled())
+        return;
+
+    if (!getScrollableArea()->layerForScrolling()) {
+        m_implOnlyAnimationUpdates.clear();
+        return;
+    }
+
+    for (auto& update : m_implOnlyAnimationUpdates) {
+        update.element_id_ = getScrollableArea()->layerForScrolling()->platformLayer()->id();
+        if (CompositorAnimationTimeline* timeline = getScrollableArea()->compositorAnimationTimeline())
+            timeline->compositorAnimationHost().addImplOnlyScrollOffsetAnimationUpdate(update);
+    }
+    m_implOnlyAnimationUpdates.clear();
+}
+
+void ScrollAnimatorCompositorCoordinator::updateImplOnlyAnimationWithAdjustment(
+    const FloatSize& adjustment)
+{
+    if (!getScrollableArea()->scrollAnimatorEnabled())
+        return;
+
+    // Note that we can't set the element_id_ here because we may not be in
+    // LifecycleState::CompositingClean and may not even have a composited layer.
+    cc::ScrollOffsetAnimationUpdate update;
+    update.type_ = cc::ScrollOffsetAnimationUpdate::Type::SCROLL_OFFSET_CHANGED;
+    update.adjustment_ = gfx::Vector2dF(adjustment.width(), adjustment.height());
+
+    m_implOnlyAnimationUpdates.push_back(update);
+    getScrollableArea()->registerForAnimation();
+}
+
 String ScrollAnimatorCompositorCoordinator::runStateAsText() const
 {
     switch (m_runState) {