Bug 1125455 patch 4 - For main-thread application of transitions, don't apply transitions when animations are also running. r=birtles

I've verified locally that this patch (not others in this series) fixes
the test failures that match the test changes in this patch.

dom/animation/Animation.cpp

@@ -297,6 +297,16 @@ Animation::ComposeStyle(nsRefPtr<css::AnimValuesStyleRule>& aStyleRule,
       continue;
     }
 
+    if (!prop.mWinsInCascade) {
+      // This isn't the winning declaration, so don't add it to style.
+      // For transitions, this is important, because it's how we
+      // implement the rule that CSS transitions don't run when a CSS
+      // animation is running on the same property and element.  For
+      // animations, this is only skipping things that will otherwise be
+      // overridden.
+      continue;
+    }
+
     aSetProperties.AddProperty(prop.mProperty);
 
     MOZ_ASSERT(prop.mSegments.Length() > 0,

layout/style/nsTransitionManager.cpp

@@ -672,6 +672,10 @@ nsTransitionManager::UpdateCascadeResults(
 
   if (changed) {
     aTransitions->UpdateAnimationGeneration(mPresContext);
+
+    // Invalidate our style rule.
+    aTransitions->mStyleRuleRefreshTime = TimeStamp();
+    aTransitions->mNeedsRefreshes = true;
   }
 }
 

layout/style/test/test_animations.html

@@ -2027,9 +2027,9 @@ is(cs.getPropertyValue("opacity"), "0.8", "opacity transition at 0s");
 advance_clock(500);
 is(cs.getPropertyValue("opacity"), "0.65", "opacity transition at 0.5s");
 div.style.animation = "opacitymid 2s linear";
-todo_is(cs.getPropertyValue("opacity"), "0.2", "opacity animation overriding transition at 0s");
+is(cs.getPropertyValue("opacity"), "0.2", "opacity animation overriding transition at 0s");
 advance_clock(500);
-todo_is(cs.getPropertyValue("opacity"), "0.35", "opacity animation overriding transition at 0.5s");
+is(cs.getPropertyValue("opacity"), "0.35", "opacity animation overriding transition at 0.5s");
 done_div();
 
 SpecialPowers.DOMWindowUtils.restoreNormalRefresh();

layout/style/test/test_animations_omta.html

@@ -2149,13 +2149,9 @@ addAsyncAnimTest(function *() {
           "opacity transition at 0.5s");
   gDiv.style.animation = "opacitymid 2s linear";
   yield waitForPaintsFlushed();
-  // FIXME: This omta_todo_is leads to a failure, since the compositor
-  // vs. main-thread check actually passes.
   omta_todo_is("opacity", 0.2, RunningOn.Compositor,
           "opacity animation overriding transition at 0s");
   advance_clock(500);
-  // FIXME: This omta_todo_is leads to a failure, since the compositor
-  // vs. main-thread check actually passes.
   omta_todo_is("opacity", 0.35, RunningOn.Compositor,
           "opacity animation overriding transition at 0.5s");
   done_div();