Resolve promises synchronously sometimes

third_party/WebKit/Source/core/animation/Animation.cpp

Index: third_party/WebKit/Source/core/animation/Animation.cpp
diff --git a/third_party/WebKit/Source/core/animation/Animation.cpp b/third_party/WebKit/Source/core/animation/Animation.cpp
index 56de1eb35efc75eba918e066a1d71393c6437358..58d7236724b35d060588822f1c74e07cc8d40e10 100644
--- a/third_party/WebKit/Source/core/animation/Animation.cpp
+++ b/third_party/WebKit/Source/core/animation/Animation.cpp
@@ -44,6 +44,7 @@
 #include "core/inspector/InspectorTraceEvents.h"
 #include "core/probe/CoreProbes.h"
 #include "platform/RuntimeEnabledFeatures.h"
+#include "platform/ScriptForbiddenScope.h"
 #include "platform/WebTaskRunner.h"
 #include "platform/animation/CompositorAnimationPlayer.h"
 #include "platform/heap/Persistent.h"
@@ -1038,9 +1039,9 @@ Animation::PlayStateUpdateScope::~PlayStateUpdateScope() {
         animation_->ready_promise_->Reject(DOMException::Create(kAbortError));
       }
       animation_->ready_promise_->Reset();
-      animation_->ResolvePromiseAsync(animation_->ready_promise_.Get());
+      animation_->ResolvePromiseMaybeAsync(animation_->ready_promise_.Get());
     } else if (old_play_state == kPending) {
-      animation_->ResolvePromiseAsync(animation_->ready_promise_.Get());
+      animation_->ResolvePromiseMaybeAsync(animation_->ready_promise_.Get());
     } else if (new_play_state == kPending) {
       DCHECK_NE(animation_->ready_promise_->GetState(),
                 AnimationPromise::kPending);
@@ -1057,7 +1058,7 @@ Animation::PlayStateUpdateScope::~PlayStateUpdateScope() {
       }
       animation_->finished_promise_->Reset();
     } else if (new_play_state == kFinished) {
-      animation_->ResolvePromiseAsync(animation_->finished_promise_.Get());
+      animation_->ResolvePromiseMaybeAsync(animation_->finished_promise_.Get());
     } else if (old_play_state == kFinished) {
       animation_->finished_promise_->Reset();
     }
@@ -1136,11 +1137,15 @@ void Animation::InvalidateKeyframeEffect(const TreeScope& tree_scope) {
                                    StyleChangeReason::kStyleSheetChange));
 }
 
-void Animation::ResolvePromiseAsync(AnimationPromise* promise) {
-  TaskRunnerHelper::Get(TaskType::kDOMManipulation, GetExecutionContext())
-      ->PostTask(BLINK_FROM_HERE,
-                 WTF::Bind(&AnimationPromise::Resolve<Animation*>,
-                           WrapPersistent(promise), WrapPersistent(this)));
+void Animation::ResolvePromiseMaybeAsync(AnimationPromise* promise) {
+  if (ScriptForbiddenScope::IsScriptForbidden()) {
+    TaskRunnerHelper::Get(TaskType::kDOMManipulation, GetExecutionContext())
+        ->PostTask(BLINK_FROM_HERE,
+                   WTF::Bind(&AnimationPromise::Resolve<Animation*>,
+                             WrapPersistent(promise), WrapPersistent(this)));
+  } else {
+    promise->Resolve(this);
+  }
 }
 
 DEFINE_TRACE(Animation) {