Revert "SkScalar: delete code thqat doesn't compile."

This reverts commit 565da18f6e.

Reason for revert:  breaking android roll:

https://googleplex-android-review.git.corp.google.com/#/c/1853481/-1..1

Some code in Android references SK_SCALAR_IS_FLOAT:
https://cs.corp.google.com/android/frameworks/base/core/jni/android/graphics/Interpolator.cpp?q=frameworks/base/core/jni/android/graphics/Interpolator.cpp&sq=package:android&l=30

Original change's description:
> SkScalar: delete code thqat doesn't compile.
> 
> Change-Id: I8a5c404d6151fca79af5c5a98d4b44924c0ade52
> Reviewed-on: https://skia-review.googlesource.com/7882
> Reviewed-by: Mike Reed <reed@google.com>
> Commit-Queue: Hal Canary <halcanary@google.com>
> 

TBR=halcanary@google.com,reed@google.com,reviews@skia.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Change-Id: I4df06c4593abaa3ac3877b270a41aec7a9c3fc8f
Reviewed-on: https://skia-review.googlesource.com/7888
Commit-Queue: Leon Scroggins <scroggo@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>

include/core/SkScalar.h

@@ -10,6 +10,14 @@
 
 #include "../private/SkFloatingPoint.h"
 
+// TODO: move this sort of check into SkPostConfig.h
+#define SK_SCALAR_IS_DOUBLE 0
+#undef SK_SCALAR_IS_FLOAT
+#define SK_SCALAR_IS_FLOAT  1
+
+
+#if SK_SCALAR_IS_FLOAT
+
 typedef float SkScalar;
 
 #define SK_Scalar1                  1.0f
@@ -48,6 +56,48 @@ typedef float SkScalar;
 #define SkScalarLog(x)              (float)sk_float_log(x)
 #define SkScalarLog2(x)             (float)sk_float_log2(x)
 
+#else   // SK_SCALAR_IS_DOUBLE
+
+typedef double SkScalar;
+
+#define SK_Scalar1                  1.0
+#define SK_ScalarHalf               0.5
+#define SK_ScalarSqrt2              1.414213562373095
+#define SK_ScalarPI                 3.141592653589793
+#define SK_ScalarTanPIOver8         0.4142135623731
+#define SK_ScalarRoot2Over2         0.70710678118655
+#define SK_ScalarMax                1.7976931348623157+308
+#define SK_ScalarInfinity           SK_DoubleInfinity
+#define SK_ScalarNegativeInfinity   SK_DoubleNegativeInfinity
+#define SK_ScalarNaN                SK_DoubleNaN
+
+#define SkScalarFloorToScalar(x)    floor(x)
+#define SkScalarCeilToScalar(x)     ceil(x)
+#define SkScalarRoundToScalar(x)    floor((x) + 0.5)
+#define SkScalarTruncToScalar(x)    trunc(x)
+
+#define SkScalarFloorToInt(x)       (int)floor(x)
+#define SkScalarCeilToInt(x)        (int)ceil(x)
+#define SkScalarRoundToInt(x)       (int)floor((x) + 0.5)
+
+#define SkScalarAbs(x)              abs(x)
+#define SkScalarCopySign(x, y)      copysign(x, y)
+#define SkScalarMod(x, y)           fmod(x,y)
+#define SkScalarSqrt(x)             sqrt(x)
+#define SkScalarPow(b, e)           pow(b, e)
+
+#define SkScalarSin(radians)        sin(radians)
+#define SkScalarCos(radians)        cos(radians)
+#define SkScalarTan(radians)        tan(radians)
+#define SkScalarASin(val)           asin(val)
+#define SkScalarACos(val)           acos(val)
+#define SkScalarATan2(y, x)         atan2(y,x)
+#define SkScalarExp(x)              exp(x)
+#define SkScalarLog(x)              log(x)
+#define SkScalarLog2(x)             log2(x)
+
+#endif
+
 //////////////////////////////////////////////////////////////////////////////////////////////////
 
 #define SkIntToScalar(x)        static_cast<SkScalar>(x)

include/private/SkFixed.h

@@ -138,9 +138,18 @@ inline SkFixed SkFixedMul_longlong(SkFixed a, SkFixed b) {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#if SK_SCALAR_IS_FLOAT
+
 #define SkFixedToScalar(x)          SkFixedToFloat(x)
 #define SkScalarToFixed(x)          SkFloatToFixed(x)
 
+#else   // SK_SCALAR_IS_DOUBLE
+
+#define SkFixedToScalar(x)          SkFixedToDouble(x)
+#define SkScalarToFixed(x)          SkDoubleToFixed(x)
+
+#endif
+
 ///////////////////////////////////////////////////////////////////////////////
 
 typedef int64_t SkFixed3232;   // 32.32

src/gpu/gl/GrGLPath.cpp

@@ -218,7 +218,7 @@ void GrGLPath::InitPathObjectPathData(GrGLGpu* gpu,
                                       const SkPath& skPath) {
     SkASSERT(!skPath.isEmpty());
 
-#if 1  //  SK_SCALAR_IS_FLOAT
+#ifdef SK_SCALAR_IS_FLOAT
     // This branch does type punning, converting SkPoint* to GrGLfloat*.
     if ((skPath.getSegmentMasks() & SkPath::kConic_SegmentMask) == 0) {
         int verbCnt = skPath.countVerbs();