Change SkTime::GetMSecs to double; ensure values stored in SkMSec do not overflow.

The following are currently unused in Android, Google3, Chromium, and Mozilla:
  - SkEvent
  - SkTime::GetMSecs
  - SK_TIME_FACTOR (also unused in Skia)
  - SkAutoTime

I left uses of SkMSec more-or-less intact for SkEvent, SkAnimator, and SkInterpolator. SkInterpolator is used in Chromium, so I did not want to change the API. The views/ and animator/ code is crufty, so it didn't seem worthwhile to refactor it. Instead, I added SkEvent::GetMSecsSinceStartup, which is likely to be adequate for use in SampleApp.

I also left SkMSec where it is used to measure a duration rather than a timestamp. With the exception of SkMovie, which is used in Android, all of the uses appear to measure the execution time of a piece of code, which I would hope does not exceed 2^31 milliseconds.

Added skiatest::Timer to support a common idiom in tests where we want to measure the wallclock time in integer milliseconds. (Not used in tests/PathOpsSkpClipTest.cpp because it redefines things in Test.h.)

Removed tabs in tests/StrokerTest.cpp.

BUG=skia:4632
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1811613004

Review URL: https://codereview.chromium.org/1811613004
diff --git a/dm/DM.cpp b/dm/DM.cpp
index ce3a1aa..34f8a96 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -73,7 +73,7 @@
 
 /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
 
-static const SkMSec kStartMs = SkTime::GetMSecs();
+static const double kStartMs = SkTime::GetMSecs();
 
 static FILE* gVLog;
 
diff --git a/gm/SkAnimTimer.h b/gm/SkAnimTimer.h
index 725171a..2c8a723 100644
--- a/gm/SkAnimTimer.h
+++ b/gm/SkAnimTimer.h
@@ -29,7 +29,7 @@
     /**
      *  Class begins in the "stopped" state.
      */
-    SkAnimTimer() : fBaseTime(0), fCurrTime(0), fState(kStopped_State) {}
+    SkAnimTimer() : fBaseTimeNanos(0), fCurrTimeNanos(0), fState(kStopped_State) {}
 
     bool isStopped() const { return kStopped_State == fState; }
     bool isRunning() const { return kRunning_State == fState; }
@@ -70,23 +70,26 @@
      */
     void updateTime() {
         if (kRunning_State == fState) {
-            fCurrTime = SkTime::GetMSecs();
+            fCurrTimeNanos = SkTime::GetNSecs();
         }
     }
 
     /**
      *  Return the time in milliseconds the timer has been in the running state.
-     *  Returns 0 if the timer is stopped.
+     *  Returns 0 if the timer is stopped. Behavior is undefined if the timer
+     *  has been running longer than SK_MSecMax.
      */
-    SkMSec msec() const { return fCurrTime - fBaseTime; }
+    SkMSec msec() const {
+        const double msec = (fCurrTimeNanos - fBaseTimeNanos) * 1e-6;
+        SkASSERT(SK_MSecMax >= msec);
+        return static_cast<SkMSec>(msec);
+    }
 
     /**
      *  Return the time in seconds the timer has been in the running state.
      *  Returns 0 if the timer is stopped.
      */
-    double secs() const {
-        return this->msec() * 0.001;
-    }
+    double secs() const { return (fCurrTimeNanos - fBaseTimeNanos) * 1e-9; }
 
     /**
      *  Return the time in seconds the timer has been in the running state,
@@ -102,14 +105,14 @@
     }
 
 private:
-    SkMSec  fBaseTime;
-    SkMSec  fCurrTime;
+    double  fBaseTimeNanos;
+    double  fCurrTimeNanos;
     State   fState;
 
     void setState(State newState) {
         switch (newState) {
             case kStopped_State:
-                fBaseTime = fCurrTime = 0;
+                fBaseTimeNanos = fCurrTimeNanos = 0;
                 fState = kStopped_State;
                 break;
             case kPaused_State:
@@ -120,12 +123,12 @@
             case kRunning_State:
                 switch (fState) {
                     case kStopped_State:
-                        fBaseTime = fCurrTime = SkTime::GetMSecs();
+                        fBaseTimeNanos = fCurrTimeNanos = SkTime::GetNSecs();
                         break;
                     case kPaused_State: {// they want "resume"
-                        SkMSec now = SkTime::GetMSecs();
-                        fBaseTime += now - fCurrTime;
-                        fCurrTime = now;
+                        double now = SkTime::GetNSecs();
+                        fBaseTimeNanos += now - fCurrTimeNanos;
+                        fCurrTimeNanos = now;
                     } break;
                     case kRunning_State:
                         break;
diff --git a/include/animator/SkAnimator.h b/include/animator/SkAnimator.h
index 9bb3642..0fe787c 100644
--- a/include/animator/SkAnimator.h
+++ b/include/animator/SkAnimator.h
@@ -443,7 +443,8 @@
     };
 
     /** Sets a user class to return the current time to the animator.
-        Optional; if not called, the system clock will be used by calling SkTime::GetMSecs instead.
+        Optional; if not called, the system clock will be used by calling
+        SkEvent::GetMSecsSinceStartup instead.
         @param callBack the time function
     */
     void setTimeline(const Timeline& );
diff --git a/include/core/SkTime.h b/include/core/SkTime.h
index 3ff29aa..8a8224a 100644
--- a/include/core/SkTime.h
+++ b/include/core/SkTime.h
@@ -34,34 +34,27 @@
     };
     static void GetDateTime(DateTime*);
 
-    static SkMSec GetMSecs() { return (SkMSec)(GetNSecs() * 1e-6); }
+    static double GetSecs() { return GetNSecs() * 1e-9; }
+    static double GetMSecs() { return GetNSecs() * 1e-6; }
     static double GetNSecs();
 };
 
-#define SK_TIME_FACTOR      1
-
 ///////////////////////////////////////////////////////////////////////////////
 
 class SkAutoTime {
 public:
     // The label is not deep-copied, so its address must remain valid for the
     // lifetime of this object
-    SkAutoTime(const char* label = NULL, SkMSec minToDump = 0) : fLabel(label)
-    {
-        fNow = SkTime::GetMSecs();
-        fMinToDump = minToDump;
-    }
-    ~SkAutoTime()
-    {
-        SkMSec dur = SkTime::GetMSecs() - fNow;
-        if (dur >= fMinToDump) {
-            SkDebugf("%s %d\n", fLabel ? fLabel : "", dur);
-        }
+    SkAutoTime(const char* label = nullptr)
+        : fLabel(label)
+        , fNow(SkTime::GetMSecs()) {}
+    ~SkAutoTime() {
+        uint64_t dur = static_cast<uint64_t>(SkTime::GetMSecs() - fNow);
+        SkDebugf("%s %ld\n", fLabel ? fLabel : "", dur);
     }
 private:
     const char* fLabel;
-    SkMSec      fNow;
-    SkMSec      fMinToDump;
+    double      fNow;
 };
 #define SkAutoTime(...) SK_REQUIRE_LOCAL_VAR(SkAutoTime)
 
diff --git a/include/core/SkTypes.h b/include/core/SkTypes.h
index d7a7911..a94a592 100644
--- a/include/core/SkTypes.h
+++ b/include/core/SkTypes.h
@@ -342,13 +342,15 @@
 /** 32 bit integer to hold a unicode value
 */
 typedef int32_t SkUnichar;
-/** 32 bit value to hold a millisecond count
-*/
+
+/** 32 bit value to hold a millisecond duration
+ *  Note that SK_MSecMax is about 25 days.
+ */
 typedef uint32_t SkMSec;
 /** 1 second measured in milliseconds
 */
 #define SK_MSec1 1000
-/** maximum representable milliseconds
+/** maximum representable milliseconds; 24d 20h 31m 23.647s.
 */
 #define SK_MSecMax 0x7FFFFFFF
 /** Returns a < b for milliseconds, correctly handling wrap-around from 0xFFFFFFFF to 0
diff --git a/include/views/SkEvent.h b/include/views/SkEvent.h
index 0af76fe..b8fc00e 100644
--- a/include/views/SkEvent.h
+++ b/include/views/SkEvent.h
@@ -206,13 +206,20 @@
     /**
      *  Post to the event queue using the event's targetID or target-proc.
      *  The event will be delivered no sooner than the specified millisecond
-     *  time, as measured by SkTime::GetMSecs().
+     *  time, as measured by GetMSecsSinceStartup().
      *
      *  The event must be dynamically allocated, as ownership is transferred to
      *  the event queue. It cannot be allocated on the stack or in a global.
      */
     void postTime(SkMSec time);
 
+    /**
+     *  Returns ~zero the first time it's called, then returns the number of
+     *  milliseconds since the first call. Behavior is undefined if the program
+     *  runs more than ~25 days.
+     */
+    static SkMSec GetMSecsSinceStartup();
+
     ///////////////////////////////////////////////
     /** Porting layer must call these functions **/
     ///////////////////////////////////////////////
diff --git a/include/views/SkTouchGesture.h b/include/views/SkTouchGesture.h
index 4a03065..60487c7 100644
--- a/include/views/SkTouchGesture.h
+++ b/include/views/SkTouchGesture.h
@@ -55,14 +55,14 @@
         float   fStartX, fStartY;
         float   fPrevX, fPrevY;
         float   fLastX, fLastY;
-        SkMSec  fPrevT, fLastT;
+        float   fPrevT, fLastT;
     };
     SkTDArray<Rec> fTouches;
 
     State           fState;
     SkMatrix        fLocalM, fGlobalM;
     SkFlingState    fFlinger;
-    SkMSec          fLastUpT;
+    double          fLastUpMillis;
     SkPoint         fLastUpP;
 
 
diff --git a/samplecode/SampleClipDrawMatch.cpp b/samplecode/SampleClipDrawMatch.cpp
index 502f349..45663b5 100644
--- a/samplecode/SampleClipDrawMatch.cpp
+++ b/samplecode/SampleClipDrawMatch.cpp
@@ -121,15 +121,15 @@
 
         fTrans.setRepeatCount(999);
         values[0] = values[1] = 0;
-        fTrans.setKeyFrame(0, SkTime::GetMSecs() + 1000, values);
+        fTrans.setKeyFrame(0, GetMSecs() + 1000, values);
         values[1] = 1;
-        fTrans.setKeyFrame(1, SkTime::GetMSecs() + 2000, values);
+        fTrans.setKeyFrame(1, GetMSecs() + 2000, values);
         values[0] = values[1] = 1;
-        fTrans.setKeyFrame(2, SkTime::GetMSecs() + 3000, values);
+        fTrans.setKeyFrame(2, GetMSecs() + 3000, values);
         values[1] = 0;
-        fTrans.setKeyFrame(3, SkTime::GetMSecs() + 4000, values);
+        fTrans.setKeyFrame(3, GetMSecs() + 4000, values);
         values[0] = 0;
-        fTrans.setKeyFrame(4, SkTime::GetMSecs() + 5000, values);
+        fTrans.setKeyFrame(4, GetMSecs() + 5000, values);
     }
 
 protected:
@@ -231,7 +231,7 @@
 
     void onDrawContent(SkCanvas* canvas) override {
         SkScalar trans[2];
-        fTrans.timeToValues(SkTime::GetMSecs(), trans);
+        fTrans.timeToValues(GetMSecs(), trans);
 
         SkPoint offset;
         offset.set(trans[0], trans[1]);
@@ -243,11 +243,16 @@
         this->inval(nullptr);
     }
 
+    SkMSec GetMSecs() const {
+        return static_cast<SkMSec>(SkTime::GetMSecs() - fStart);
+    }
+
 private:
     SkInterpolator  fTrans;
     Geometry        fGeom;
     bool            fClipFirst;
     int             fSign;
+    const double    fStart = SkTime::GetMSecs();
 
     typedef SampleView INHERITED;
 };
diff --git a/src/animator/SkAnimateMaker.cpp b/src/animator/SkAnimateMaker.cpp
index 0c28c7b..5186da0 100644
--- a/src/animator/SkAnimateMaker.cpp
+++ b/src/animator/SkAnimateMaker.cpp
@@ -23,7 +23,7 @@
 
 class DefaultTimeline : public SkAnimator::Timeline {
     virtual SkMSec getMSecs() const {
-        return SkTime::GetMSecs();
+        return SkEvent::GetMSecsSinceStartup();
     }
 } gDefaultTimeline;
 
diff --git a/src/pdf/SkPDFMetadata.cpp b/src/pdf/SkPDFMetadata.cpp
index 5e8c124..118cda3 100644
--- a/src/pdf/SkPDFMetadata.cpp
+++ b/src/pdf/SkPDFMetadata.cpp
@@ -55,7 +55,7 @@
     SkMD5 md5;
     const char uuidNamespace[] = "org.skia.pdf\n";
     md5.write(uuidNamespace, strlen(uuidNamespace));
-    SkMSec msec = SkTime::GetMSecs();
+    double msec = SkTime::GetMSecs();
     md5.write(&msec, sizeof(msec));
     SkTime::DateTime dateTime;
     SkTime::GetDateTime(&dateTime);
diff --git a/src/views/SkEvent.cpp b/src/views/SkEvent.cpp
index 5316b49..b90d03f 100644
--- a/src/views/SkEvent.cpp
+++ b/src/views/SkEvent.cpp
@@ -298,7 +298,7 @@
     }
 
     if (delay) {
-        this->postTime(SkTime::GetMSecs() + delay);
+        this->postTime(GetMSecsSinceStartup() + delay);
         return;
     }
 
@@ -404,7 +404,7 @@
         prev->fNextEvent = evt;
     }
 
-    SkMSec delay = globals.fDelayQHead->fTime - SkTime::GetMSecs();
+    SkMSec delay = globals.fDelayQHead->fTime - GetMSecsSinceStartup();
     if ((int32_t)delay <= 0) {
         delay = 1;
     }
@@ -436,7 +436,7 @@
     globals.fEventMutex.acquire();
 
     bool        wasEmpty = false;
-    SkMSec      now = SkTime::GetMSecs();
+    SkMSec      now = GetMSecsSinceStartup();
     SkEvent*    evt = globals.fDelayQHead;
 
     while (evt)
@@ -485,6 +485,11 @@
     return count;
 }
 
+SkMSec SkEvent::GetMSecsSinceStartup() {
+    static const double kEpoch = SkTime::GetMSecs();
+    return static_cast<SkMSec>(SkTime::GetMSecs() - kEpoch);
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 void SkEvent::Init() {}
diff --git a/src/views/SkTouchGesture.cpp b/src/views/SkTouchGesture.cpp
index 22c9434..676f8e9 100644
--- a/src/views/SkTouchGesture.cpp
+++ b/src/views/SkTouchGesture.cpp
@@ -115,7 +115,7 @@
     fLocalM.reset();
     fGlobalM.reset();
 
-    fLastUpT = SkTime::GetMSecs() - 2*MAX_DBL_TAP_INTERVAL;
+    fLastUpMillis = SkTime::GetMSecs() - 2*MAX_DBL_TAP_INTERVAL;
     fLastUpP.set(0, 0);
 }
 
@@ -138,7 +138,7 @@
     rec->fOwner = owner;
     rec->fStartX = rec->fPrevX = rec->fLastX = x;
     rec->fStartY = rec->fPrevY = rec->fLastY = y;
-    rec->fLastT = rec->fPrevT = SkTime::GetMSecs();
+    rec->fLastT = rec->fPrevT = static_cast<float>(SkTime::GetSecs());
 }
 
 void SkTouchGesture::touchBegin(void* owner, float x, float y) {
@@ -227,7 +227,8 @@
 
     rec.fPrevX = rec.fLastX; rec.fLastX = x;
     rec.fPrevY = rec.fLastY; rec.fLastY = y;
-    rec.fPrevT = rec.fLastT; rec.fLastT = SkTime::GetMSecs();
+    rec.fPrevT = rec.fLastT;
+    rec.fLastT = static_cast<float>(SkTime::GetSecs());
 
     switch (fTouches.count()) {
         case 1: {
@@ -276,7 +277,7 @@
             this->flushLocalM();
             float dx = rec.fLastX - rec.fPrevX;
             float dy = rec.fLastY - rec.fPrevY;
-            float dur = (rec.fLastT - rec.fPrevT) * 0.001f;
+            float dur = rec.fLastT - rec.fPrevT;
             if (dur > 0) {
                 fFlinger.reset(dx / dur, dy / dur);
             }
@@ -310,8 +311,8 @@
 
 bool SkTouchGesture::handleDblTap(float x, float y) {
     bool found = false;
-    SkMSec now = SkTime::GetMSecs();
-    if (now - fLastUpT <= MAX_DBL_TAP_INTERVAL) {
+    double now = SkTime::GetMSecs();
+    if (now - fLastUpMillis <= MAX_DBL_TAP_INTERVAL) {
         if (SkPoint::Length(fLastUpP.fX - x,
                             fLastUpP.fY - y) <= MAX_DBL_TAP_DISTANCE) {
             fFlinger.stop();
@@ -323,7 +324,7 @@
         }
     }
 
-    fLastUpT = now;
+    fLastUpMillis = now;
     fLastUpP.set(x, y);
     return found;
 }
diff --git a/tests/PathOpsSkpClipTest.cpp b/tests/PathOpsSkpClipTest.cpp
index d11f8e0..b5fd58d 100644
--- a/tests/PathOpsSkpClipTest.cpp
+++ b/tests/PathOpsSkpClipTest.cpp
@@ -215,7 +215,7 @@
     TestStep fTestStep;
     int fDirNo;
     int fPixelError;
-    int fTime;
+    SkMSec fTime;
     int fScale;
 };
 
@@ -372,7 +372,7 @@
         }
     }
     int slowCount = data->fSlowest.count();
-    int time = testResult.fTime;
+    SkMSec time = testResult.fTime;
     if (time > 0) {
         for (int index = 0; index < slowCount; ++index) {
             if (time > data->fSlowest[index].fTime) {
@@ -402,7 +402,7 @@
     SkScalar yInterval = SkTMax(pHeight - maxDimension, 0.0f) / (slices - 1);
     SkRect rect = {0, 0, SkTMin(maxDimension, pWidth), SkTMin(maxDimension, pHeight) };
     canvas->clipRect(rect);
-    SkMSec start = SkTime::GetMSecs();
+    double start = SkTime::GetMSecs();
     for (int x = 0; x < slices; ++x) {
         for (int y = 0; y < slices; ++y) {
             pic->playback(canvas);
@@ -410,9 +410,9 @@
         }
         canvas->translate(xInterval, -yInterval * slices);
     }
-    SkMSec end = SkTime::GetMSecs();
+    double end = SkTime::GetMSecs();
     canvas->restore();
-    return end - start;
+    return static_cast<SkMSec>(end - start);
 }
 
 static void drawPict(SkPicture* pic, SkCanvas* canvas, int scale) {
@@ -502,9 +502,9 @@
         drawPict(pic.get(), &opCanvas, fScale);
         if (fTestStep == kCompareBits) {
             fPixelError = similarBits(oldBitmap, opBitmap);
-            int oldTime = timePict(pic.get(), &oldCanvas);
-            int opTime = timePict(pic.get(), &opCanvas);
-            fTime = SkTMax(0, oldTime - opTime);
+            SkMSec oldTime = timePict(pic.get(), &oldCanvas);
+            SkMSec opTime = timePict(pic.get(), &opCanvas);
+            fTime = SkTMax(static_cast<SkMSec>(0), oldTime - opTime);
         } else if (fTestStep == kEncodeFiles) {
             SkString pngStr = make_png_name(fFilename);
             const char* pngName = pngStr.c_str();
diff --git a/tests/SkpSkGrTest.cpp b/tests/SkpSkGrTest.cpp
index 23bec84..4469d4f 100644
--- a/tests/SkpSkGrTest.cpp
+++ b/tests/SkpSkGrTest.cpp
@@ -106,7 +106,7 @@
     TestStep fTestStep;
     int fDirNo;
     int fPixelError;
-    int fTime;
+    SkMSec fTime;
     bool fScaleOversized;
 };
 
@@ -343,7 +343,7 @@
     SkRect rect = {0, 0, SkIntToScalar(SkTMin(maxDimension, pWidth)),
             SkIntToScalar(SkTMin(maxDimension, pHeight))};
     canvas->clipRect(rect);
-    SkMSec start = SkTime::GetMSecs();
+    skiatest::Timer timer;
     for (int x = 0; x < slices; ++x) {
         for (int y = 0; y < slices; ++y) {
             pic->draw(canvas);
@@ -351,9 +351,9 @@
         }
         canvas->translate(SkIntToScalar(xInterval), SkIntToScalar(-yInterval * slices));
     }
-    SkMSec end = SkTime::GetMSecs();
+    SkMSec elapsed = timer.elapsedMsInt();
     canvas->restore();
-    return end - start;
+    return elapsed;
 }
 
 static void drawPict(SkPicture* pic, SkCanvas* canvas, int scale) {
@@ -462,8 +462,8 @@
 
         if (fTestStep == kCompareBits) {
             fPixelError = similarBits(grBitmap, bitmap);
-            int skTime = timePict(pic, &skCanvas);
-            int grTime = timePict(pic, &grCanvas);
+            SkMSec skTime = timePict(pic, &skCanvas);
+            SkMSec grTime = timePict(pic, &grCanvas);
             fTime = skTime - grTime;
         } else if (fTestStep == kEncodeFiles) {
             SkString pngStr = make_png_name(fFilename);
diff --git a/tests/StrokerTest.cpp b/tests/StrokerTest.cpp
index b588cc6..68792d9 100755
--- a/tests/StrokerTest.cpp
+++ b/tests/StrokerTest.cpp
@@ -1,3 +1,10 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
 #include "PathOpsCubicIntersectionTestData.h"
 #include "PathOpsQuadIntersectionTestData.h"
 #include "SkCommonFlags.h"
@@ -20,7 +27,7 @@
 
 static void pathTest(const SkPath& path) {
     SkPaint p;
-	SkPath fill;
+    SkPath fill;
     p.setStyle(SkPaint::kStroke_Style);
     for (size_t index = 0; index < widths_count; ++index) {
         p.setStrokeWidth(widths[index]);
@@ -29,91 +36,91 @@
 }
 
 static void cubicTest(const SkPoint c[4]) {
-	SkPath path;
-	path.moveTo(c[0].fX, c[0].fY);
-	path.cubicTo(c[1].fX, c[1].fY, c[2].fX, c[2].fY, c[3].fX, c[3].fY);
-	pathTest(path);
+    SkPath path;
+    path.moveTo(c[0].fX, c[0].fY);
+    path.cubicTo(c[1].fX, c[1].fY, c[2].fX, c[2].fY, c[3].fX, c[3].fY);
+    pathTest(path);
 }
 
 static void quadTest(const SkPoint c[3]) {
-	SkPath path;
-	path.moveTo(c[0].fX, c[0].fY);
-	path.quadTo(c[1].fX, c[1].fY, c[2].fX, c[2].fY);
-	pathTest(path);
+    SkPath path;
+    path.moveTo(c[0].fX, c[0].fY);
+    path.quadTo(c[1].fX, c[1].fY, c[2].fX, c[2].fY);
+    pathTest(path);
 }
 
 static void cubicSetTest(const SkDCubic* dCubic, size_t count) {
-    SkMSec limit = SkTime::GetMSecs() + MS_TEST_DURATION;
-	for (size_t index = 0; index < count; ++index) {
-		const SkDCubic& d = dCubic[index];
-		SkPoint c[4] = { {(float) d[0].fX, (float) d[0].fY}, {(float) d[1].fX, (float) d[1].fY},
+    skiatest::Timer timer;
+    for (size_t index = 0; index < count; ++index) {
+        const SkDCubic& d = dCubic[index];
+        SkPoint c[4] = { {(float) d[0].fX, (float) d[0].fY}, {(float) d[1].fX, (float) d[1].fY},
                          {(float) d[2].fX, (float) d[2].fY}, {(float) d[3].fX, (float) d[3].fY} };
-	    cubicTest(c);
-        if (FLAGS_timeout && SkTime::GetMSecs() > limit) {
+        cubicTest(c);
+        if (FLAGS_timeout && timer.elapsedMs() > MS_TEST_DURATION) {
             return;
         }
-	}
+    }
 }
 
 static void cubicPairSetTest(const SkDCubic dCubic[][2], size_t count) {
-    SkMSec limit = SkTime::GetMSecs() + MS_TEST_DURATION;
-	for (size_t index = 0; index < count; ++index) {
-		for (int pair = 0; pair < 2; ++pair) {
-			const SkDCubic& d = dCubic[index][pair];
-			SkPoint c[4] = { {(float) d[0].fX, (float) d[0].fY}, {(float) d[1].fX, (float) d[1].fY},
+    skiatest::Timer timer;
+    for (size_t index = 0; index < count; ++index) {
+        for (int pair = 0; pair < 2; ++pair) {
+            const SkDCubic& d = dCubic[index][pair];
+            SkPoint c[4] = { {(float) d[0].fX, (float) d[0].fY}, {(float) d[1].fX, (float) d[1].fY},
                              {(float) d[2].fX, (float) d[2].fY}, {(float) d[3].fX, (float) d[3].fY} };
-			cubicTest(c);
-            if (FLAGS_timeout && SkTime::GetMSecs() > limit) {
+            cubicTest(c);
+            if (FLAGS_timeout && timer.elapsedMs() > MS_TEST_DURATION) {
                 return;
             }
-		}
-	}
+        }
+    }
 }
 
 static void quadSetTest(const SkDQuad* dQuad, size_t count) {
-    SkMSec limit = SkTime::GetMSecs() + MS_TEST_DURATION;
-	for (size_t index = 0; index < count; ++index) {
-		const SkDQuad& d = dQuad[index];
-		SkPoint c[3] = { {(float) d[0].fX, (float) d[0].fY}, {(float) d[1].fX, (float) d[1].fY},
+    skiatest::Timer timer;
+    for (size_t index = 0; index < count; ++index) {
+        const SkDQuad& d = dQuad[index];
+        SkPoint c[3] = { {(float) d[0].fX, (float) d[0].fY}, {(float) d[1].fX, (float) d[1].fY},
                          {(float) d[2].fX, (float) d[2].fY}  };
-	    quadTest(c);
-        if (FLAGS_timeout && SkTime::GetMSecs() > limit) {
+        quadTest(c);
+        if (FLAGS_timeout && timer.elapsedMs() > MS_TEST_DURATION) {
             return;
         }
-	}
+    }
 }
 
 static void quadPairSetTest(const SkDQuad dQuad[][2], size_t count) {
-    SkMSec limit = SkTime::GetMSecs() + MS_TEST_DURATION;
-	for (size_t index = 0; index < count; ++index) {
-		for (int pair = 0; pair < 2; ++pair) {
-			const SkDQuad& d = dQuad[index][pair];
-			SkPoint c[3] = { {(float) d[0].fX, (float) d[0].fY}, {(float) d[1].fX, (float) d[1].fY},
+    skiatest::Timer timer;
+    for (size_t index = 0; index < count; ++index) {
+        for (int pair = 0; pair < 2; ++pair) {
+            const SkDQuad& d = dQuad[index][pair];
+            SkPoint c[3] = { {(float) d[0].fX, (float) d[0].fY}, {(float) d[1].fX, (float) d[1].fY},
                              {(float) d[2].fX, (float) d[2].fY}  };
-			quadTest(c);
-            if (FLAGS_timeout && SkTime::GetMSecs() > limit) {
+            quadTest(c);
+            if (FLAGS_timeout && timer.elapsedMs() > MS_TEST_DURATION) {
                 return;
             }
-		}
-	}
+        }
+    }
 }
 
 DEF_TEST(QuadStrokerSet, reporter) {
-	quadSetTest(quadraticLines, quadraticLines_count);
-	quadSetTest(quadraticPoints, quadraticPoints_count);
-	quadSetTest(quadraticModEpsilonLines, quadraticModEpsilonLines_count);
-	quadPairSetTest(quadraticTests, quadraticTests_count);
+    quadSetTest(quadraticLines, quadraticLines_count);
+    quadSetTest(quadraticPoints, quadraticPoints_count);
+    quadSetTest(quadraticModEpsilonLines, quadraticModEpsilonLines_count);
+    quadPairSetTest(quadraticTests, quadraticTests_count);
 }
 
 DEF_TEST(CubicStrokerSet, reporter) {
-	cubicSetTest(pointDegenerates, pointDegenerates_count);
-	cubicSetTest(notPointDegenerates, notPointDegenerates_count);
-	cubicSetTest(lines, lines_count);
-	cubicSetTest(notLines, notLines_count);
-	cubicSetTest(modEpsilonLines, modEpsilonLines_count);
-	cubicSetTest(lessEpsilonLines, lessEpsilonLines_count);
-	cubicSetTest(negEpsilonLines, negEpsilonLines_count);
-	cubicPairSetTest(tests, tests_count);
+    cubicSetTest(pointDegenerates, pointDegenerates_count);
+    cubicSetTest(notPointDegenerates, notPointDegenerates_count);
+    cubicSetTest(lines, lines_count);
+    cubicSetTest(notLines, notLines_count);
+    cubicSetTest(modEpsilonLines, modEpsilonLines_count);
+    cubicSetTest(lessEpsilonLines, lessEpsilonLines_count);
+    cubicSetTest(negEpsilonLines, negEpsilonLines_count);
+    cubicPairSetTest(tests, tests_count);
 }
 
 static SkScalar unbounded(SkRandom& r) {
@@ -134,7 +141,7 @@
     int best = 0;
     sk_bzero(gMaxRecursion, sizeof(gMaxRecursion[0]) * 3);
 #endif
-    SkMSec limit = SkTime::GetMSecs() + MS_TEST_DURATION;
+    skiatest::Timer timer;
     for (int i = 0; i < 1000000; ++i) {
         SkPath path, fill;
         path.moveTo(unbounded(r), unbounded(r));
@@ -153,7 +160,7 @@
             best = gMaxRecursion[2];
         }
 #endif
-        if (FLAGS_timeout && SkTime::GetMSecs() > limit) {
+        if (FLAGS_timeout && timer.elapsedMs() > MS_TEST_DURATION) {
             return;
         }
     }
@@ -173,7 +180,7 @@
     int bestCubic = 0;
     sk_bzero(gMaxRecursion, sizeof(gMaxRecursion[0]) * 3);
 #endif
-    SkMSec limit = SkTime::GetMSecs() + MS_TEST_DURATION;
+    skiatest::Timer timer;
     for (int i = 0; i < 1000000; ++i) {
         SkPath path, fill;
         path.moveTo(unbounded(r), unbounded(r));
@@ -194,7 +201,7 @@
             bestCubic = SkTMax(bestCubic, gMaxRecursion[1]);
         }
     #endif
-        if (FLAGS_timeout && SkTime::GetMSecs() > limit) {
+        if (FLAGS_timeout && timer.elapsedMs() > MS_TEST_DURATION) {
             return;
         }
     }
@@ -213,7 +220,7 @@
     int best = 0;
     sk_bzero(gMaxRecursion, sizeof(gMaxRecursion[0]) * 3);
 #endif
-    SkMSec limit = SkTime::GetMSecs() + MS_TEST_DURATION;
+    skiatest::Timer timer;
     for (int i = 0; i < 1000000; ++i) {
         SkPath path, fill;
         SkPoint quad[3];
@@ -245,7 +252,7 @@
             best = gMaxRecursion[2];
         }
 #endif
-        if (FLAGS_timeout && SkTime::GetMSecs() > limit) {
+        if (FLAGS_timeout && timer.elapsedMs() > MS_TEST_DURATION) {
             return;
         }
     }
@@ -265,7 +272,7 @@
     int bestCubic = 0;
     sk_bzero(gMaxRecursion, sizeof(gMaxRecursion[0]) * 3);
 #endif
-    SkMSec limit = SkTime::GetMSecs() + MS_TEST_DURATION;
+    skiatest::Timer timer;
     for (int i = 0; i < 1000000; ++i) {
         SkPath path, fill;
         SkPoint cubic[4];
@@ -304,7 +311,7 @@
             bestCubic = SkTMax(bestCubic, gMaxRecursion[1]);
         }
 #endif
-        if (FLAGS_timeout && SkTime::GetMSecs() > limit) {
+        if (FLAGS_timeout && timer.elapsedMs() > MS_TEST_DURATION) {
             return;
         }
     }
@@ -323,7 +330,7 @@
     int best = 0;
     sk_bzero(gMaxRecursion, sizeof(gMaxRecursion[0]) * 3);
 #endif
-    SkMSec limit = SkTime::GetMSecs() + MS_TEST_DURATION;
+    skiatest::Timer timer;
     for (int i = 0; i < 1000000; ++i) {
         SkPath path, fill;
         SkPoint quad[3];
@@ -349,7 +356,7 @@
             best = gMaxRecursion[2];
         }
 #endif
-        if (FLAGS_timeout && SkTime::GetMSecs() > limit) {
+        if (FLAGS_timeout && timer.elapsedMs() > MS_TEST_DURATION) {
             return;
         }
     }
@@ -368,7 +375,7 @@
     int best[2] = { 0 };
     sk_bzero(gMaxRecursion, sizeof(gMaxRecursion[0]) * 3);
 #endif
-    SkMSec limit = SkTime::GetMSecs() + MS_TEST_DURATION;
+    skiatest::Timer timer;
     for (int i = 0; i < 1000000; ++i) {
         SkPath path, fill;
         path.moveTo(r.nextRangeF(0, 500), r.nextRangeF(0, 500));
@@ -389,7 +396,7 @@
             best[1] = SkTMax(best[1], gMaxRecursion[1]);
         }
 #endif
-        if (FLAGS_timeout && SkTime::GetMSecs() > limit) {
+        if (FLAGS_timeout && timer.elapsedMs() > MS_TEST_DURATION) {
             return;
         }
     }
diff --git a/tests/Test.cpp b/tests/Test.cpp
index f6f2bda..dcb08e6 100644
--- a/tests/Test.cpp
+++ b/tests/Test.cpp
@@ -36,3 +36,17 @@
     const char* tmpDir = FLAGS_tmpDir.isEmpty() ? nullptr : FLAGS_tmpDir[0];
     return SkString(tmpDir);
 }
+
+skiatest::Timer::Timer() : fStartNanos(SkTime::GetNSecs()) {}
+
+double skiatest::Timer::elapsedNs() const {
+    return SkTime::GetNSecs() - fStartNanos;
+}
+
+double skiatest::Timer::elapsedMs() const { return this->elapsedNs() * 1e-6; }
+
+SkMSec skiatest::Timer::elapsedMsInt() const {
+    const double elapsedMs = this->elapsedMs();
+    SkASSERT(SK_MSecMax >= elapsedMs);
+    return static_cast<SkMSec>(elapsedMs);
+}
diff --git a/tests/Test.h b/tests/Test.h
index d643c83..411ce11 100644
--- a/tests/Test.h
+++ b/tests/Test.h
@@ -85,6 +85,27 @@
 template<typename T>
 void RunWithGPUTestContexts(T testFunction, GPUTestContexts contexts, Reporter* reporter,
                             GrContextFactory* factory);
+
+/** Timer provides wall-clock duration since its creation. */
+class Timer {
+public:
+    /** Starts the timer. */
+    Timer();
+
+    /** Nanoseconds since creation. */
+    double elapsedNs() const;
+
+    /** Milliseconds since creation. */
+    double elapsedMs() const;
+
+    /** Milliseconds since creation as an integer.
+        Behavior is undefined for durations longer than SK_MSecMax.
+    */
+    SkMSec elapsedMsInt() const;
+private:
+    double fStartNanos;
+};
+
 }  // namespace skiatest
 
 #define REPORTER_ASSERT(r, cond)                  \
diff --git a/tests/skia_test.cpp b/tests/skia_test.cpp
index 65fbc32..5d21d1e 100644
--- a/tests/skia_test.cpp
+++ b/tests/skia_test.cpp
@@ -95,9 +95,9 @@
           int fTestCount;
       } reporter;
 
-      const SkMSec start = SkTime::GetMSecs();
+      const Timer timer;
       fTest.proc(&reporter, fGrContextFactory);
-      SkMSec elapsed = SkTime::GetMSecs() - start;
+      SkMSec elapsed = timer.elapsedMsInt();
       if (reporter.fError) {
           fStatus->reportFailure();
       }