Compositor animations for Independent CSS Transform Properties

Source/core/animation/KeyframeEffect.cpp

Index: Source/core/animation/KeyframeEffect.cpp
diff --git a/Source/core/animation/KeyframeEffect.cpp b/Source/core/animation/KeyframeEffect.cpp
index 0afa07e9837f71cf7e403be29b4d57eaf5ac9465..8b3a4fd7768c19778893bb09ee135f760970bc72 100644
--- a/Source/core/animation/KeyframeEffect.cpp
+++ b/Source/core/animation/KeyframeEffect.cpp
@@ -139,14 +139,13 @@ void KeyframeEffect::applyEffects()
     // Cancel composited animation of transform if a motion path, translate,
     // rotate or scale operation has been introduced on the element.
     if (m_target->computedStyle()
-        && (m_target->computedStyle()->hasMotionPath()
-            || m_target->computedStyle()->translate()
-            || m_target->computedStyle()->rotate()
-            || m_target->computedStyle()->scale())
+        && m_target->computedStyle()->hasMotionPath()
         && animation()->hasActiveAnimationsOnCompositor()
-        && animation()->affects(*m_target, CSSPropertyTransform)) {
+        && (animation()->affects(*m_target, CSSPropertyScale)
+            || animation()->affects(*m_target, CSSPropertyRotate)
+            || animation()->affects(*m_target, CSSPropertyTransform)
+            || animation()->affects(*m_target, CSSPropertyTranslate)))
         animation()->cancelAnimationOnCompositor();
-    }
 
     double iteration = currentIteration();
     ASSERT(iteration >= 0);
@@ -246,9 +245,25 @@ bool KeyframeEffect::isCandidateForAnimationOnCompositor(double animationPlaybac
 {
     if (!model()
         || !m_target
-        || (m_target->computedStyle() && (m_target->computedStyle()->hasMotionPath() || m_target->computedStyle()->translate() || m_target->computedStyle()->rotate() || m_target->computedStyle()->scale())))
+        || (m_target->computedStyle() && m_target->computedStyle()->hasMotionPath()))
         return false;
 
+    // Do not put transforms on compositor if more than one of them are defined
+    // in computed style because they need to be explicitly ordered
+    if (m_target->computedStyle()) {
+        unsigned transformOperationsCount = 0;
+        if (m_target->computedStyle()->hasTransformOperations())
+            transformOperationsCount++;
+        if (m_target->computedStyle()->rotate())
+            transformOperationsCount++;
+        if (m_target->computedStyle()->scale())
+            transformOperationsCount++;
+        if (m_target->computedStyle()->translate())
+            transformOperationsCount++;
+        if (transformOperationsCount > 1)
+            return false;
+    }
+
     return CompositorAnimations::instance()->isCandidateForAnimationOnCompositor(specifiedTiming(), *m_target, animation(), *model(), animationPlaybackRate);
 }