samples: gpu: removed inclusion of non-existent opencv2/contrib/contrib.hpp header, re-introduced TickMeter class in a separate header

This patch removes inclusion of opencv2/contrib/contrib.hpp header,
which does not exist anymore due to removal of opencv_contrib module.

The samples including this header appear to be doing so in order to
use TickMeter class; therefore, the latter is now provided by tick_meter.hpp
header file, located in samples/gpu folder.

samples/gpu/tick_meter.hpp

@@ -0,0 +1,48 @@
+#ifndef OPENCV_CUDA_SAMPLES_TICKMETER_
+#define OPENCV_CUDA_SAMPLES_TICKMETER_
+
+class CV_EXPORTS TickMeter
+{
+public:
+    TickMeter();
+    void start();
+    void stop();
+
+    int64 getTimeTicks() const;
+    double getTimeMicro() const;
+    double getTimeMilli() const;
+    double getTimeSec()   const;
+    int64 getCounter() const;
+
+    void reset();
+private:
+    int64 counter;
+    int64 sumTime;
+    int64 startTime;
+};
+
+std::ostream& operator << (std::ostream& out, const TickMeter& tm);
+
+
+TickMeter::TickMeter() { reset(); }
+int64 TickMeter::getTimeTicks() const { return sumTime; }
+double TickMeter::getTimeMicro() const { return (double)getTimeTicks()/cv::getTickFrequency(); }
+double TickMeter::getTimeMilli() const { return getTimeMicro()*1e-3; }
+double TickMeter::getTimeSec() const { return getTimeMilli()*1e-3; }
+int64 TickMeter::getCounter() const { return counter; }
+void TickMeter::reset() {startTime = 0; sumTime = 0; counter = 0; }
+
+void TickMeter::start(){ startTime = cv::getTickCount(); }
+void TickMeter::stop()
+{
+    int64 time = cv::getTickCount();
+    if ( startTime == 0 )
+        return;
+    ++counter;
+    sumTime += ( time - startTime );
+    startTime = 0;
+}
+
+std::ostream& operator << (std::ostream& out, const TickMeter& tm) { return out << tm.getTimeSec() << "sec"; }
+
+#endif