Reland toBlob: If idle image encoding is postponed for too long, switch to main thread

third_party/WebKit/Source/core/html/canvas/CanvasAsyncBlobCreatorTest.cpp

Index: third_party/WebKit/Source/core/html/canvas/CanvasAsyncBlobCreatorTest.cpp
diff --git a/third_party/WebKit/Source/core/html/canvas/CanvasAsyncBlobCreatorTest.cpp b/third_party/WebKit/Source/core/html/canvas/CanvasAsyncBlobCreatorTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..7ac15c7330155856be6083c6126663e130ee9172
--- /dev/null
+++ b/third_party/WebKit/Source/core/html/canvas/CanvasAsyncBlobCreatorTest.cpp
@@ -0,0 +1,188 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/html/canvas/CanvasAsyncBlobCreator.h"
+
+#include "core/html/ImageData.h"
+#include "platform/Task.h"
+#include "platform/testing/UnitTestHelpers.h"
+#include "public/platform/Platform.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "wtf/Functional.h"
+
+namespace blink {
+
+typedef CanvasAsyncBlobCreator::IdleTaskStatus IdleTaskStatus;
+
+class MockCanvasAsyncBlobCreator : public CanvasAsyncBlobCreator {
+public:
+    MockCanvasAsyncBlobCreator(DOMUint8ClampedArray* data, const IntSize& size)
+        : CanvasAsyncBlobCreator(data, "image/png", size, nullptr)
+    {
+    }
+
+    CanvasAsyncBlobCreator::IdleTaskStatus idleTaskStatus()
+    {
+        return m_idleTaskStatus;
+    }
+
+    MOCK_METHOD0(signalTaskSwitchInStartTimeoutEventForTesting, void());
+    MOCK_METHOD0(signalTaskSwitchInCompleteTimeoutEventForTesting, void());
+
+protected:
+    void createBlobAndInvokeCallback() override { };
+    void createNullAndInvokeCallback() override { };
+    void signalAlternativeCodePathFinishedForTesting() override;
+    void postDelayedTaskToMainThread(const WebTraceLocation&, SameThreadTask*, double delayMs) override;
+};
+
+void MockCanvasAsyncBlobCreator::signalAlternativeCodePathFinishedForTesting()
+{
+    testing::exitRunLoop();
+}
+
+void MockCanvasAsyncBlobCreator::postDelayedTaskToMainThread(const WebTraceLocation& location, SameThreadTask* task, double delayMs)
+{
+    Platform::current()->mainThread()->getWebTaskRunner()->postTask(location, task);
+}
+
+//==============================================================================
+
+class MockCanvasAsyncBlobCreatorWithoutStart : public MockCanvasAsyncBlobCreator {
+public:
+    MockCanvasAsyncBlobCreatorWithoutStart(DOMUint8ClampedArray* data, const IntSize& size)
+        : MockCanvasAsyncBlobCreator(data, size)
+    {
+    }
+
+protected:
+    void scheduleInitiatePngEncoding() override
+    {
+        // Deliberately make scheduleInitiatePngEncoding do nothing so that idle task never starts
+    }
+};
+
+//==============================================================================
+
+class MockCanvasAsyncBlobCreatorWithoutComplete : public MockCanvasAsyncBlobCreator {
+public:
+    MockCanvasAsyncBlobCreatorWithoutComplete(DOMUint8ClampedArray* data, const IntSize& size)
+        : MockCanvasAsyncBlobCreator(data, size)
+    {
+    }
+
+protected:
+    void scheduleInitiatePngEncoding() override
+    {
+        Platform::current()->mainThread()->getWebTaskRunner()->postTask(BLINK_FROM_HERE,
+        bind(&MockCanvasAsyncBlobCreatorWithoutComplete::initiatePngEncoding, this, std::numeric_limits<double>::max()));
+    }
+
+    void idleEncodeRowsPng(double deadlineSeconds) override
+    {
+        // Deliberately make idleEncodeRowsPng do nothing so that idle task never completes
+    }
+};
+
+//==============================================================================
+
+class CanvasAsyncBlobCreatorTest : public ::testing::Test {
+public:
+    void prepareMockCanvasAsyncBlobCreatorWithoutStart();
+    void prepareMockCanvasAsyncBlobCreatorWithoutComplete();
+    void prepareMockCanvasAsyncBlobCreatorFail();
+
+protected:
+    CanvasAsyncBlobCreatorTest();
+    MockCanvasAsyncBlobCreator* asyncBlobCreator() { return m_asyncBlobCreator.get(); }
+    void TearDown() override;
+
+private:
+    Persistent<MockCanvasAsyncBlobCreator> m_asyncBlobCreator;
+};
+
+CanvasAsyncBlobCreatorTest::CanvasAsyncBlobCreatorTest()
+{
+}
+
+void CanvasAsyncBlobCreatorTest::prepareMockCanvasAsyncBlobCreatorWithoutStart()
+{
+    IntSize testSize(20, 20);
+    ImageData* imageData = ImageData::create(testSize);
+
+    m_asyncBlobCreator = new MockCanvasAsyncBlobCreatorWithoutStart(imageData->data(), testSize);
+}
+
+void CanvasAsyncBlobCreatorTest::prepareMockCanvasAsyncBlobCreatorWithoutComplete()
+{
+    IntSize testSize(20, 20);
+    ImageData* imageData = ImageData::create(testSize);
+
+    m_asyncBlobCreator = new MockCanvasAsyncBlobCreatorWithoutComplete(imageData->data(), testSize);
+}
+
+void CanvasAsyncBlobCreatorTest::prepareMockCanvasAsyncBlobCreatorFail()
+{
+    IntSize testSize(0, 0);
+    ImageData* imageData = ImageData::create(testSize);
+
+    // We reuse the class MockCanvasAsyncBlobCreatorWithoutComplete because this
+    // test case is expected to fail at initialization step before completion.
+    m_asyncBlobCreator = new MockCanvasAsyncBlobCreatorWithoutComplete(imageData->data(), testSize);
+}
+
+void CanvasAsyncBlobCreatorTest::TearDown()
+{
+    m_asyncBlobCreator = nullptr;
+}
+
+//==============================================================================
+
+TEST_F(CanvasAsyncBlobCreatorTest, IdleTaskNotStartedWhenStartTimeoutEventHappens)
+{
+    // This test mocks the scenario when idle task is not started when the
+    // StartTimeoutEvent is inspecting the idle task status.
+    // The whole image encoding process (including initialization)  will then
+    // become carried out in the alternative code path instead.
+    this->prepareMockCanvasAsyncBlobCreatorWithoutStart();
+    EXPECT_CALL(*(asyncBlobCreator()), signalTaskSwitchInStartTimeoutEventForTesting());
+
+    this->asyncBlobCreator()->scheduleAsyncBlobCreation(true);
+    testing::enterRunLoop();
+
+    ::testing::Mock::VerifyAndClearExpectations(asyncBlobCreator());
+    EXPECT_EQ(IdleTaskStatus::IdleTaskSwitchedToMainThreadTask, this->asyncBlobCreator()->idleTaskStatus());
+}
+
+TEST_F(CanvasAsyncBlobCreatorTest, IdleTaskNotCompletedWhenCompleteTimeoutEventHappens)
+{
+    // This test mocks the scenario when idle task is not completed when the
+    // CompleteTimeoutEvent is inspecting the idle task status.
+    // The remaining image encoding process (excluding initialization)  will
+    // then become carried out in the alternative code path instead.
+    this->prepareMockCanvasAsyncBlobCreatorWithoutComplete();
+    EXPECT_CALL(*(asyncBlobCreator()), signalTaskSwitchInCompleteTimeoutEventForTesting());
+
+    this->asyncBlobCreator()->scheduleAsyncBlobCreation(true);
+    testing::enterRunLoop();
+
+    ::testing::Mock::VerifyAndClearExpectations(asyncBlobCreator());
+    EXPECT_EQ(IdleTaskStatus::IdleTaskSwitchedToMainThreadTask, this->asyncBlobCreator()->idleTaskStatus());
+}
+
+TEST_F(CanvasAsyncBlobCreatorTest, IdleTaskFailedWhenStartTimeoutEventHappens)
+{
+    // This test mocks the scenario when idle task is not failed during when
+    // either the StartTimeoutEvent or the CompleteTimeoutEvent is inspecting
+    // the idle task status.
+    this->prepareMockCanvasAsyncBlobCreatorFail();
+
+    this->asyncBlobCreator()->scheduleAsyncBlobCreation(true);
+    testing::enterRunLoop();
+
+    EXPECT_EQ(IdleTaskStatus::IdleTaskFailed, this->asyncBlobCreator()->idleTaskStatus());
+}
+
+}