Add support for Low Priorirty tasks.

Source/platform/scheduler/SchedulerTest.cpp

Index: Source/platform/scheduler/SchedulerTest.cpp
diff --git a/Source/platform/scheduler/SchedulerTest.cpp b/Source/platform/scheduler/SchedulerTest.cpp
index 557e0386c2b070ffab155b9a6b0ebbdb7b79e976..95057dc6cbf6ed72040226d449f805de6982d353 100644
--- a/Source/platform/scheduler/SchedulerTest.cpp
+++ b/Source/platform/scheduler/SchedulerTest.cpp
@@ -8,13 +8,17 @@
 #include "platform/TestingPlatformSupport.h"
 #include "platform/TraceLocation.h"
 #include "public/platform/Platform.h"
+#include "public/platform/WebBeginFrameArgs.h"
 #include "public/platform/WebThread.h"
+#include "wtf/CurrentTime.h"
 
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
+#include <queue>
 #include <string>
 #include <vector>
 
+using blink::Platform;
 using blink::Scheduler;
 
 namespace {
@@ -29,7 +33,8 @@ public:
 
     virtual void postDelayedTask(Task* task, long long delayMs) OVERRIDE
     {
-        ASSERT_NOT_REACHED();
+        long long deadline = static_cast<long long>(Platform::current()->monotonicallyIncreasingTime() * 1000.0) + delayMs;
+        m_pendingDelayedTasks.push(DelayedTask(deadline, adoptPtr(task)));
     }
 
     virtual bool isCurrentThread() const OVERRIDE
@@ -51,6 +56,12 @@ public:
     {
         while (!m_pendingTasks.isEmpty())
             m_pendingTasks.takeFirst()->run();
+
+        long long timeMs = static_cast<long long>(Platform::current()->monotonicallyIncreasingTime() * 1000.0);
+        while (!m_pendingDelayedTasks.empty() && m_pendingDelayedTasks.top().m_deadline <= timeMs) {
+            m_pendingDelayedTasks.top().run();
+            m_pendingDelayedTasks.pop();
+        }
     }
 
     size_t numPendingMainThreadTasks() const
@@ -58,8 +69,43 @@ public:
         return m_pendingTasks.size();
     }
 
+    double nextDelayedTaskDeadlineOrMinusOne() const
+    {
+        if (m_pendingDelayedTasks.empty())
+            return -1;
+
+        return static_cast<double>(m_pendingDelayedTasks.top().m_deadline) * 0.001;
+    }
+
 private:
+    class DelayedTask {
+    public:
+        DelayedTask(long long deadline, PassOwnPtr<WebThread::Task> task)
+            : m_deadline(deadline)
+            , m_task(task.leakPtr())
+        {
+        }
+
+        void run() const
+        {
+            m_task->run();
+            delete m_task;
+        }
+
+        bool operator<(const DelayedTask& other) const
+        {
+            return m_deadline > other.m_deadline;
+        }
+
+        long long m_deadline;
+
+        // NOTE we can't use OwnPtr<> here because the std::priority_queue uses the copy constructor
+        // and c++11 style move semantics are not allowed yet.
+        WebThread::Task* m_task;
+    };
+
     WTF::Deque<OwnPtr<Task> > m_pendingTasks;
+    std::priority_queue<DelayedTask> m_pendingDelayedTasks;
 };
 
 class SchedulerTestingPlatformSupport : blink::TestingPlatformSupport {
@@ -70,6 +116,12 @@ public:
         , m_sharedTimerRunning(false)
         , m_sharedTimerFireInterval(0)
     {
+        WTF::setMonotonicallyIncreasingTimeFunction(getDebugTime);
+    }
+
+    virtual ~SchedulerTestingPlatformSupport()
+    {
+        WTF::setMonotonicallyIncreasingTimeFunction(0);
     }
 
     // blink::Platform implementation.
@@ -83,6 +135,11 @@ public:
         m_sharedTimerFunction = timerFunction;
     }
 
+    virtual double monotonicallyIncreasingTime() OVERRIDE
+    {
+        return s_debugTime;
+    }
+
     virtual void setSharedTimerFireInterval(double)
     {
         m_sharedTimerFireInterval = 0;
@@ -119,13 +176,31 @@ public:
         return m_mainThread.numPendingMainThreadTasks();
     }
 
+    double nextDelayedTaskDeadlineOrMinusOne() const
+    {
+        return m_mainThread.nextDelayedTaskDeadlineOrMinusOne();
+    }
+
+    static void setDebugTime(double time)
+    {
+        s_debugTime = time;
+    }
+
 private:
+    static double getDebugTime(void)
+    {
+        return s_debugTime;
+    }
     TestMainThread m_mainThread;
     SharedTimerFunction m_sharedTimerFunction;
     bool m_sharedTimerRunning;
     double m_sharedTimerFireInterval;
+
+    static double s_debugTime;
 };
 
+double SchedulerTestingPlatformSupport::s_debugTime = 0;
+
 class SchedulerTest : public testing::Test {
 public:
     SchedulerTest()
@@ -215,13 +290,16 @@ TEST_F(SchedulerTest, TestPostTask)
 
 TEST_F(SchedulerTest, TestPostMixedTaskTypes)
 {
+    SchedulerTestingPlatformSupport::setDebugTime(1000.0);
     int result = 0;
     m_scheduler->postTask(FROM_HERE, WTF::bind(&unorderedTestTask, 1, &result));
     m_scheduler->postInputTask(FROM_HERE, WTF::bind(&unorderedTestTask, 2, &result));
     m_scheduler->postCompositorTask(FROM_HERE, WTF::bind(&unorderedTestTask, 4, &result));
     m_scheduler->postTask(FROM_HERE, WTF::bind(&unorderedTestTask, 8, &result));
+    m_scheduler->postIpcTask(FROM_HERE, WTF::bind(&unorderedTestTask, 16, &result));
+    SchedulerTestingPlatformSupport::setDebugTime(1001.0);
     runPendingTasks();
-    EXPECT_EQ(15, result);
+    EXPECT_EQ(31, result);
 }
 
 int s_sharedTimerTickCount;
@@ -262,16 +340,21 @@ TEST_F(SchedulerTest, TestIdleTask)
 
 TEST_F(SchedulerTest, TestTaskPrioritization)
 {
+    SchedulerTestingPlatformSupport::setDebugTime(1000.0);
+    m_scheduler->postIpcTask(FROM_HERE, WTF::bind(&SchedulerTest::appendToVector, this, std::string("IPC1")));
+    m_scheduler->postIpcTask(FROM_HERE, WTF::bind(&SchedulerTest::appendToVector, this, std::string("IPC2")));
     m_scheduler->postTask(FROM_HERE, WTF::bind(&SchedulerTest::appendToVector, this, std::string("L1")));
     m_scheduler->postTask(FROM_HERE, WTF::bind(&SchedulerTest::appendToVector, this, std::string("L2")));
     m_scheduler->postInputTask(FROM_HERE, WTF::bind(&SchedulerTest::appendToVector, this, std::string("I1")));
     m_scheduler->postCompositorTask(FROM_HERE, WTF::bind(&SchedulerTest::appendToVector, this, std::string("C1")));
     m_scheduler->postInputTask(FROM_HERE, WTF::bind(&SchedulerTest::appendToVector, this, std::string("I2")));
     m_scheduler->postCompositorTask(FROM_HERE, WTF::bind(&SchedulerTest::appendToVector, this, std::string("C2")));
+    SchedulerTestingPlatformSupport::setDebugTime(1001.0);
 
     runPendingTasks();
     EXPECT_THAT(m_order, testing::ElementsAre(
-        std::string("I1"), std::string("C1"), std::string("I2"), std::string("C2"), std::string("L1"), std::string("L2")));
+        std::string("I1"), std::string("C1"), std::string("I2"), std::string("C2"), std::string("L1"), std::string("L2"),
+        std::string("IPC1"), std::string("IPC2")));
 }
 
 TEST_F(SchedulerTest, TestRentrantTask)
@@ -393,4 +476,49 @@ TEST_F(SchedulerTest, HighPriorityTasksOnlyRunOncePerSharedTimerFiring)
     m_scheduler->setSharedTimerFiredFunction(nullptr);
 }
 
+TEST_F(SchedulerTest, TestNextPredictedCompositorStart_initialState)
+{
+    SchedulerTestingPlatformSupport::setDebugTime(1000.0);
+    EXPECT_EQ(0, m_scheduler->nextPredictedCompositorStart());
+}
+
+TEST_F(SchedulerTest, TestNextPredictedCompositorDeadline_initialState)
+{
+    SchedulerTestingPlatformSupport::setDebugTime(1000.0);
+    EXPECT_EQ(0, m_scheduler->nextPredictedCompositorDeadline());
+}
+
+TEST_F(SchedulerTest, TestNextPredictedCompositorStart_afterWillBeginFrame)
+{
+    m_scheduler->willBeginFrame(blink::WebBeginFrameArgs(999.8, 999.9, 0.2));
+
+    // NOTE nextPredictedCompositorStart attempts to return a time in the future.
+    SchedulerTestingPlatformSupport::setDebugTime(999.999);
+    EXPECT_DOUBLE_EQ(1000.0, m_scheduler->nextPredictedCompositorStart());
+
+    SchedulerTestingPlatformSupport::setDebugTime(1000.0);
+    EXPECT_DOUBLE_EQ(1000.2, m_scheduler->nextPredictedCompositorStart());
+}
+
+TEST_F(SchedulerTest, TestNextPredictedCompositorDeadline_afterWillBeginFrame)
+{
+    m_scheduler->willBeginFrame(blink::WebBeginFrameArgs(999.8, 999.9, 0.2));
+
+    // NOTE nextPredictedCompositorStart attempts to return a time in the future.
+    SchedulerTestingPlatformSupport::setDebugTime(1000.0);
+    EXPECT_DOUBLE_EQ(1000.1, m_scheduler->nextPredictedCompositorDeadline());
+
+    SchedulerTestingPlatformSupport::setDebugTime(1000.2);
+    EXPECT_DOUBLE_EQ(1000.3, m_scheduler->nextPredictedCompositorDeadline());
+}
+
+TEST_F(SchedulerTest, TestLowPriorityTasksPostedAtNextComposiorDeadline)
+{
+    m_scheduler->willBeginFrame(blink::WebBeginFrameArgs(999.8, 999.9, 0.2));
+    SchedulerTestingPlatformSupport::setDebugTime(1000.0);
+
+    m_scheduler->postIpcTask(FROM_HERE, WTF::bind(&dummyTask));
+    EXPECT_DOUBLE_EQ(1000.1, m_platformSupport.nextDelayedTaskDeadlineOrMinusOne());
+}
+
 } // namespace