Support OffscreenCanvas transfer with V8-based structured clone.

BUG=148757

Review-Url: https://codereview.chromium.org/2361253002
Cr-Commit-Position: refs/heads/master@{#420582}

third_party/WebKit/Source/bindings/core/v8/serialization/V8ScriptValueDeserializer.cpp

@@ -10,6 +10,7 @@
 #include "core/dom/MessagePort.h"
 #include "core/frame/ImageBitmap.h"
 #include "core/html/ImageData.h"
+#include "core/offscreencanvas/OffscreenCanvas.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "wtf/CheckedNumeric.h"
 
@@ -149,6 +150,21 @@ ScriptWrappable* V8ScriptValueDeserializer::readDOMObject(SerializationTag tag)
             return nullptr;
         return (*m_transferredMessagePorts)[index].get();
     }
+    case OffscreenCanvasTransferTag: {
+        uint32_t width = 0, height = 0, canvasId = 0, clientId = 0, localId = 0;
+        uint64_t nonce = 0;
+        if (!readUint32(&width)
+            || !readUint32(&height)
+            || !readUint32(&canvasId)
+            || !readUint32(&clientId)
+            || !readUint32(&localId)
+            || !readUint64(&nonce))
+            return nullptr;
+        OffscreenCanvas* canvas = OffscreenCanvas::create(width, height);
+        canvas->setAssociatedCanvasId(canvasId);
+        canvas->setSurfaceId(clientId, localId, nonce);
+        return canvas;
+    }
     default:
         break;
     }

third_party/WebKit/Source/bindings/core/v8/serialization/V8ScriptValueSerializer.cpp

@@ -8,6 +8,7 @@
 #include "bindings/core/v8/V8ImageBitmap.h"
 #include "bindings/core/v8/V8ImageData.h"
 #include "bindings/core/v8/V8MessagePort.h"
+#include "bindings/core/v8/V8OffscreenCanvas.h"
 #include "core/dom/DOMArrayBufferBase.h"
 #include "core/html/ImageData.h"
 #include "platform/RuntimeEnabledFeatures.h"
@@ -103,6 +104,10 @@ void V8ScriptValueSerializer::finalizeTransfer(ExceptionState& exceptionState)
     m_serializedScriptValue->transferImageBitmaps(isolate, m_transferables->imageBitmaps, exceptionState);
     if (exceptionState.hadException())
         return;
+
+    m_serializedScriptValue->transferOffscreenCanvas(isolate, m_transferables->offscreenCanvases, exceptionState);
+    if (exceptionState.hadException())
+        return;
 }
 
 void V8ScriptValueSerializer::writeUTF8String(const String& string)
@@ -176,6 +181,32 @@ bool V8ScriptValueSerializer::writeDOMObject(ScriptWrappable* wrappable, Excepti
         writeUint32(static_cast<uint32_t>(index));
         return true;
     }
+    if (wrapperTypeInfo == &V8OffscreenCanvas::wrapperTypeInfo) {
+        OffscreenCanvas* canvas = wrappable->toImpl<OffscreenCanvas>();
+        size_t index = kNotFound;
+        if (m_transferables)
+            index = m_transferables->offscreenCanvases.find(canvas);
+        if (index == kNotFound) {
+            exceptionState.throwDOMException(DataCloneError, "An OffscreenCanvas could not be cloned because it was not transferred.");
+            return false;
+        }
+        if (canvas->isNeutered()) {
+            exceptionState.throwDOMException(DataCloneError, "An OffscreenCanvas could not be cloned because it was detached.");
+            return false;
+        }
+        if (canvas->renderingContext()) {
+            exceptionState.throwDOMException(DataCloneError, "An OffscreenCanvas could not be cloned because it had a rendering context.");
+            return false;
+        }
+        writeTag(OffscreenCanvasTransferTag);
+        writeUint32(canvas->width());
+        writeUint32(canvas->height());
+        writeUint32(canvas->getAssociatedCanvasId());
+        writeUint32(canvas->clientId());
+        writeUint32(canvas->localId());
+        writeUint64(canvas->nonce());
+        return true;
+    }
     return false;
 }
 

third_party/WebKit/Source/bindings/core/v8/serialization/V8ScriptValueSerializerTest.cpp

@@ -12,11 +12,13 @@
 #include "bindings/core/v8/V8ImageBitmap.h"
 #include "bindings/core/v8/V8ImageData.h"
 #include "bindings/core/v8/V8MessagePort.h"
+#include "bindings/core/v8/V8OffscreenCanvas.h"
 #include "bindings/core/v8/V8StringResource.h"
 #include "bindings/core/v8/serialization/V8ScriptValueDeserializer.h"
 #include "core/dom/MessagePort.h"
 #include "core/frame/LocalFrame.h"
 #include "core/html/ImageData.h"
+#include "core/offscreencanvas/OffscreenCanvas.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/graphics/StaticBitmapImage.h"
 #include "public/platform/WebMessagePortChannel.h"
@@ -463,5 +465,24 @@ TEST(V8ScriptValueSerializerTest, TransferImageBitmap)
     EXPECT_TRUE(imageBitmap->isNeutered());
 }
 
+TEST(V8ScriptValueSerializerTest, TransferOffscreenCanvas)
+{
+    // More exhaustive tests in LayoutTests/. This is a sanity check.
+    ScopedEnableV8BasedStructuredClone enable;
+    V8TestingScope scope;
+    OffscreenCanvas* canvas = OffscreenCanvas::create(10, 7);
+    canvas->setAssociatedCanvasId(519);
+    v8::Local<v8::Value> wrapper = toV8(canvas, scope.getScriptState());
+    Transferables transferables;
+    transferables.offscreenCanvases.append(canvas);
+    v8::Local<v8::Value> result = roundTrip(wrapper, scope, nullptr, &transferables);
+    ASSERT_TRUE(V8OffscreenCanvas::hasInstance(result, scope.isolate()));
+    OffscreenCanvas* newCanvas = V8OffscreenCanvas::toImpl(result.As<v8::Object>());
+    EXPECT_EQ(IntSize(10, 7), newCanvas->size());
+    EXPECT_EQ(519, newCanvas->getAssociatedCanvasId());
+    EXPECT_TRUE(canvas->isNeutered());
+    EXPECT_FALSE(newCanvas->isNeutered());
+}
+
 } // namespace
 } // namespace blink