Add bench for SkDDLRecorder detach

On Windows I'm getting:

curr/maxrss	loops	min	median	mean	max	stddev	samples   	config	bench
  33/38  MB	1495	2.62us	2.65us	2.66us	2.72us	1%	.o.o.oO.OO	gl	DDLRecorder

Change-Id: I529e6ac612c455915c166472124b08647eb7bffd
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/241039
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>

bench/DDLRecorderBench.cpp

@@ -0,0 +1,88 @@
+/*
+ * 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 "bench/Benchmark.h"
+
+#include "include/core/SkDeferredDisplayListRecorder.h"
+#include "include/core/SkSurfaceCharacterization.h"
+
+static SkSurfaceCharacterization create_characterization(GrContext* context) {
+    size_t maxResourceBytes = context->getResourceCacheLimit();
+
+    if (!context->colorTypeSupportedAsSurface(kRGBA_8888_SkColorType)) {
+        return SkSurfaceCharacterization();
+    }
+
+    SkImageInfo ii = SkImageInfo::Make(32, 32, kRGBA_8888_SkColorType,
+                                       kPremul_SkAlphaType, nullptr);
+
+    GrBackendFormat backendFormat = context->defaultBackendFormat(kRGBA_8888_SkColorType,
+                                                                  GrRenderable::kYes);
+    if (!backendFormat.isValid()) {
+        return SkSurfaceCharacterization();
+    }
+
+    SkSurfaceProps props(0x0, kUnknown_SkPixelGeometry);
+
+    SkSurfaceCharacterization c = context->threadSafeProxy()->createCharacterization(
+                                                        maxResourceBytes, ii, backendFormat, 1,
+                                                        kTopLeft_GrSurfaceOrigin, props, false);
+    return c;
+}
+
+// This benchmark tries to simulate how Viz is using SkDDLRecorders.
+// For each config it will create a single DDLRecorder which it reuses for all the runs
+// For each run it creates a DDL and stores it for later deletion.
+class DDLRecorderBench : public Benchmark {
+public:
+    DDLRecorderBench() { }
+
+protected:
+    const char* onGetName() override { return "DDLRecorder"; }
+
+    void onDraw(int loops, SkCanvas* origCanvas) override {
+        if (!fRecorder) {
+            return;
+        }
+
+        SkASSERT(!fDDLs.size());
+        fDDLs.reserve(loops);
+
+        for (int i = 0; i < loops; ++i) {
+            SkCanvas* recordingCanvas = fRecorder->getCanvas();
+
+            recordingCanvas->drawRect(SkRect::MakeWH(32, 32), SkPaint());
+
+            fDDLs.emplace_back(fRecorder->detach());
+        }
+    }
+
+private:
+    // We create one DDLRecorder for all the timing runs and just keep reusing it
+    void onPerCanvasPreDraw(SkCanvas* origCanvas) override {
+        GrContext* context = origCanvas->getGrContext();
+        if (!context) {
+            return;
+        }
+
+        SkSurfaceCharacterization c = create_characterization(context);
+
+        fRecorder.reset(new SkDeferredDisplayListRecorder(c));
+    }
+
+    // We defer the clean up of the DDLs so it is done outside of the timing loop
+    void onPostDraw(SkCanvas*) override {
+        fDDLs.clear();
+    }
+
+    std::unique_ptr<SkDeferredDisplayListRecorder>      fRecorder = nullptr;
+    std::vector<std::unique_ptr<SkDeferredDisplayList>> fDDLs;
+
+    typedef Benchmark INHERITED;
+};
+
+DEF_BENCH(return new DDLRecorderBench();)

gn/bench.gni

@@ -39,6 +39,7 @@ bench_sources = [
   "$_bench/CubicKLMBench.cpp",
   "$_bench/CubicMapBench.cpp",
   "$_bench/DashBench.cpp",
+  "$_bench/DDLRecorderBench.cpp",
   "$_bench/DisplacementBench.cpp",
   "$_bench/DrawBitmapAABench.cpp",
   "$_bench/DrawLatticeBench.cpp",