diff --git a/src/gpu/GrWaitRenderTask.cpp b/src/gpu/GrWaitRenderTask.cpp
new file mode 100644
index 0000000..a09a9a6
--- /dev/null
+++ b/src/gpu/GrWaitRenderTask.cpp
@@ -0,0 +1,28 @@
+/*
+ * Copyright 2019 Google LLC
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "src/gpu/GrWaitRenderTask.h"
+
+#include "src/gpu/GrGpu.h"
+#include "src/gpu/GrOpFlushState.h"
+#include "src/gpu/GrResourceAllocator.h"
+
+void GrWaitRenderTask::gatherProxyIntervals(GrResourceAllocator* alloc) const {
+    // This renderTask doesn't have "normal" ops. In this case we still need to add an interval (so
+    // fEndOfOpsTaskOpIndices will remain in sync), so we create a fake op# to capture the fact that
+    // we manipulate fTarget.
+    alloc->addInterval(fTarget.get(), alloc->curOp(), alloc->curOp(),
+                       GrResourceAllocator::ActualUse::kYes);
+    alloc->incOps();
+}
+
+bool GrWaitRenderTask::onExecute(GrOpFlushState* flushState) {
+    for (int i = 0; i < fNumSemaphores; ++i) {
+        flushState->gpu()->waitSemaphore(fSemaphores[i]);
+    }
+    return true;
+}