Revert of fix zero-length tangent

tests/GeometryTest.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkGeometry.h"
 #include "Test.h"
 #include "SkRandom.h"
@@ skipping 87 matching lines @@
             SkScalar t = dt;
             for (int j = 1; j < 128; ++j) {
                 test_conic_eval_pos(reporter, conic, t);
                 test_conic_eval_tan(reporter, conic, t);
                 t += dt;
             }
         }
     }
 }
 
-static void test_quad_tangents(skiatest::Reporter* reporter) {
-    SkPoint pts[] = {
-        {10, 20}, {10, 20}, {20, 30},
-        {10, 20}, {15, 25}, {20, 30},
-        {10, 20}, {20, 30}, {20, 30},
-    };
-    int count = (int) SK_ARRAY_COUNT(pts) / 3;
-    for (int index = 0; index < count; ++index) {
-        SkConic conic(&pts[index * 3], 0.707f);
-        SkVector start = SkEvalQuadTangentAt(&pts[index * 3], 0);
-        SkVector mid = SkEvalQuadTangentAt(&pts[index * 3], .5f);
-        SkVector end = SkEvalQuadTangentAt(&pts[index * 3], 1);
-        REPORTER_ASSERT(reporter, start.fX && start.fY);
-        REPORTER_ASSERT(reporter, mid.fX && mid.fY);
-        REPORTER_ASSERT(reporter, end.fX && end.fY);
-        REPORTER_ASSERT(reporter, SkScalarNearlyZero(start.cross(mid)));
-        REPORTER_ASSERT(reporter, SkScalarNearlyZero(mid.cross(end)));
-    }
-}
-
-static void test_conic_tangents(skiatest::Reporter* reporter) {
-    SkPoint pts[] = {
-        { 10, 20}, {10, 20}, {20, 30},
-        { 10, 20}, {15, 25}, {20, 30},
-        { 10, 20}, {20, 30}, {20, 30}
-    };
-    int count = (int) SK_ARRAY_COUNT(pts) / 3;
-    for (int index = 0; index < count; ++index) {
-        SkConic conic(&pts[index * 3], 0.707f);
-        SkVector start = conic.evalTangentAt(0);
-        SkVector mid = conic.evalTangentAt(.5f);
-        SkVector end = conic.evalTangentAt(1);
-        REPORTER_ASSERT(reporter, start.fX && start.fY);
-        REPORTER_ASSERT(reporter, mid.fX && mid.fY);
-        REPORTER_ASSERT(reporter, end.fX && end.fY);
-        REPORTER_ASSERT(reporter, SkScalarNearlyZero(start.cross(mid)));
-        REPORTER_ASSERT(reporter, SkScalarNearlyZero(mid.cross(end)));
-    }
-}
-
-static void test_cubic_tangents(skiatest::Reporter* reporter) {
-    SkPoint pts[] = {
-        { 10, 20}, {10, 20}, {20, 30}, {30, 40},
-        { 10, 20}, {15, 25}, {20, 30}, {30, 40},
-        { 10, 20}, {20, 30}, {30, 40}, {30, 40},
-    };
-    int count = (int) SK_ARRAY_COUNT(pts) / 4;
-    for (int index = 0; index < count; ++index) {
-        SkConic conic(&pts[index * 3], 0.707f);
-        SkVector start, mid, end;
-        SkEvalCubicAt(&pts[index * 4], 0, NULL, &start, NULL);
-        SkEvalCubicAt(&pts[index * 4], .5f, NULL, &mid, NULL);
-        SkEvalCubicAt(&pts[index * 4], 1, NULL, &end, NULL);
-        REPORTER_ASSERT(reporter, start.fX && start.fY);
-        REPORTER_ASSERT(reporter, mid.fX && mid.fY);
-        REPORTER_ASSERT(reporter, end.fX && end.fY);
-        REPORTER_ASSERT(reporter, SkScalarNearlyZero(start.cross(mid)));
-        REPORTER_ASSERT(reporter, SkScalarNearlyZero(mid.cross(end)));
-    }
-}
-
 DEF_TEST(Geometry, reporter) {
     SkPoint pts[3], dst[5];
 
     pts[0].set(0, 0);
     pts[1].set(100, 50);
     pts[2].set(0, 100);
 
     int count = SkChopQuadAtMaxCurvature(pts, dst);
     REPORTER_ASSERT(reporter, count == 1 || count == 2);
 
     pts[0].set(0, 0);
     pts[1].set(3, 0);
     pts[2].set(3, 3);
     SkConvertQuadToCubic(pts, dst);
     const SkPoint cubic[] = {
         { 0, 0, }, { 2, 0, }, { 3, 1, }, { 3, 3 },
     };
     for (int i = 0; i < 4; ++i) {
         REPORTER_ASSERT(reporter, nearly_equal(cubic[i], dst[i]));
     }
 
     testChopCubic(reporter);
     test_evalquadat(reporter);
     test_conic(reporter);
-    test_cubic_tangents(reporter);
-    test_quad_tangents(reporter);
-    test_conic_tangents(reporter);
 }