[Experimental] Supporting OOPIF printing

skia/ext/SkFutureDrawable.cc

Index: skia/ext/SkFutureDrawable.cc
diff --git a/skia/ext/SkFutureDrawable.cc b/skia/ext/SkFutureDrawable.cc
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+++ b/skia/ext/SkFutureDrawable.cc
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+/*
+ * Copyright 2017 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "skia/ext/SkFutureDrawable.h"
+
+#include "base/logging.h"
+#include "third_party/skia/include/core/SkCanvas.h"
+#include "third_party/skia/include/core/SkPictureRecorder.h"
+#include "third_party/skia/include/core/SkScalar.h"
+#include "third_party/skia/include/core/SkWriteBuffer.h"
+#include "third_party/skia/src/core/SkReadBuffer.h"
+
+const char SkFutureDrawable::kTypeName[] = "SkFutureDrawable";
+
+std::unordered_map<int, std::unique_ptr<SkDrawable>>
+    SkFutureDrawable::fDrawableRefMap = {};
+
+void SkFutureDrawable::flatten(SkWriteBuffer& buffer) const {
+  // Write the bounds.
+  buffer.writeRect(fBounds);
+  // Write the unique id.
+  buffer.writeInt(id);
+}
+
+// static
+sk_sp<SkFlattenable> SkFutureDrawable::CreateProc(SkReadBuffer& buffer) {
+  // Read the bounds.
+  SkRect bounds;
+  buffer.readRect(&bounds);
+
+  // Read the unique id.
+  int id = buffer.readInt();
+  sk_sp<SkFutureDrawable> drawable = sk_make_sp<SkFutureDrawable>(bounds, id);
+
+  // Check whether the drawable reference is there
+  const auto ptr = fDrawableRefMap.find(id);
+  if (ptr != fDrawableRefMap.end())
+    drawable->setDrawableRef(ptr->second.get());
+
+  return drawable;
+}
+
+void SkFutureDrawable::onDraw(SkCanvas* canvas) {
+  if (!fDrawableRef)
+    return;
+  fDrawableRef->draw(canvas);
+}
+
+SkPicture* SkFutureDrawable::onNewPictureSnapshot() {
+  SkPictureRecorder recorder;
+
+  SkCanvas* canvas = recorder.beginRecording(fBounds, nullptr, 0);
+  canvas->translate(fBounds.x(), fBounds.y());
+  draw(canvas);
+  return recorder.finishRecordingAsPicture().release();
+}