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..c7937e5f2a096f5a7fec18156369c49aa7fde8ae 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_implOnlyAnimationAdjustments.empty())
+        return true;
+
     switch (m_runState) {
     case RunState::Idle:
     case RunState::RunningOnCompositor:
@@ -238,6 +242,41 @@ FloatPoint ScrollAnimatorCompositorCoordinator::blinkOffsetFromCompositorOffset(
     return offset;
 }
 
+void ScrollAnimatorCompositorCoordinator::updateCompositorAnimations()
+{
+    if (!getScrollableArea()->scrollAnimatorEnabled())
+        return;
+
+    CompositorAnimationTimeline* timeline = getScrollableArea()->compositorAnimationTimeline();
+    if (!getScrollableArea()->layerForScrolling() || !timeline) {
+        m_implOnlyAnimationAdjustments.clear();
+        return;
+    }
+
+    CompositorAnimationHost host = timeline->compositorAnimationHost();
+    if (host.isNull()) {
+        m_implOnlyAnimationAdjustments.clear();
+        return;
+    }
+
+    for (auto& update : m_implOnlyAnimationAdjustments) {

[loyso (OOO), 2016/05/16 02:50:37]

Nit: You could call .clear() only once at the end of this function, without any
premature returns.
Surround the main action with something like
if (getScrollableArea()->layerForScrolling() && timeline &&
!timeline->compositorAnimationHost().isNull())
for example (or similar)

[ymalik, 2016/05/16 18:21:36]

Done.

+        cc::ElementId elementId = getScrollableArea()->layerForScrolling()->platformLayer()->id();
+        host.updateImplOnlyScrollOffsetAnimation(
+            gfx::Vector2dF(update.width(), update.height()), elementId);
+    }
+    m_implOnlyAnimationAdjustments.clear();
+}
+
+void ScrollAnimatorCompositorCoordinator::updateImplOnlyScrollOffsetAnimation(
+    const FloatSize& adjustment)
+{
+    if (!getScrollableArea()->scrollAnimatorEnabled())
+        return;
+
+    m_implOnlyAnimationAdjustments.push_back(adjustment);
+    getScrollableArea()->registerForAnimation();
+}
+
 String ScrollAnimatorCompositorCoordinator::runStateAsText() const
 {
     switch (m_runState) {