remove Sk64 from public API, and start to remove usage internally

src/core/SkRegion_path.cpp

Index: src/core/SkRegion_path.cpp
diff --git a/src/core/SkRegion_path.cpp b/src/core/SkRegion_path.cpp
index a20647c9663da3f6f53e3d99cd3217a4d8e6d7c9..95247f403e8db29f81e93398c10e8c1b617758c6 100644
--- a/src/core/SkRegion_path.cpp
+++ b/src/core/SkRegion_path.cpp
@@ -107,8 +107,6 @@ bool SkRgnBuilder::init(int maxHeight, int maxTransitions, bool pathIsInverse) {
         return false;
     }
 
-    Sk64 count, size;
-
     if (pathIsInverse) {
         // allow for additional X transitions to "invert" each scanline
         // [ L' ... normal transitions ... R' ]
@@ -117,25 +115,25 @@ bool SkRgnBuilder::init(int maxHeight, int maxTransitions, bool pathIsInverse) {
     }
 
     // compute the count with +1 and +3 slop for the working buffer
-    count.setMul(maxHeight + 1, 3 + maxTransitions);
+    int64_t count = sk_64_mul(maxHeight + 1, 3 + maxTransitions);
 
     if (pathIsInverse) {
         // allow for two "empty" rows for the top and bottom
         //      [ Y, 1, L, R, S] == 5 (*2 for top and bottom)
-        count.add(10);
+        count += 10;
     }
 
-    if (!count.is32() || count.isNeg()) {
+    if (count < 0 || !sk_64_isS32(count)) {
         return false;
     }
-    fStorageCount = count.get32();
+    fStorageCount = sk_64_asS32(count);
 
-    size.setMul(fStorageCount, sizeof(SkRegion::RunType));
-    if (!size.is32() || size.isNeg()) {
+    int64_t size = sk_64_mul(fStorageCount, sizeof(SkRegion::RunType));
+    if (size < 0 || !sk_64_isS32(size)) {
         return false;
     }
 
-    fStorage = (SkRegion::RunType*)sk_malloc_flags(size.get32(), 0);
+    fStorage = (SkRegion::RunType*)sk_malloc_flags(sk_64_asS32(size), 0);
     if (NULL == fStorage) {
         return false;
     }