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/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();
       }