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

tests/BitmapCopyTest.cpp

Index: tests/BitmapCopyTest.cpp
diff --git a/tests/BitmapCopyTest.cpp b/tests/BitmapCopyTest.cpp
index 455fc691e3ec004a3c8433d6eb095b37b68559b9..7a1d9acd7cba13d488eda82fb8c07762e26144e4 100644
--- a/tests/BitmapCopyTest.cpp
+++ b/tests/BitmapCopyTest.cpp
@@ -343,8 +343,8 @@
             SkBitmap tstSafeSize;
             tstSafeSize.setConfig(gPairs[i].fConfig, 100000000U,
                                   100000000U);
-            int64_t safeSize = tstSafeSize.computeSafeSize64();
-            if (safeSize < 0) {
+            Sk64 safeSize = tstSafeSize.getSafeSize64();
+            if (safeSize.isNeg()) {
                 SkString str;
                 str.printf("getSafeSize64() negative: %s",
                     getSkConfigName(tstSafeSize));
@@ -358,20 +358,20 @@
 
                 case SkBitmap::kA8_Config:
                 case SkBitmap::kIndex8_Config:
-                    if (safeSize != 0x2386F26FC10000LL) {
+                    if (safeSize.as64() != 0x2386F26FC10000LL) {
                         sizeFail = true;
                     }
                     break;
 
                 case SkBitmap::kRGB_565_Config:
                 case SkBitmap::kARGB_4444_Config:
-                    if (safeSize != 0x470DE4DF820000LL) {
+                    if (safeSize.as64() != 0x470DE4DF820000LL) {
                         sizeFail = true;
                     }
                     break;
 
                 case SkBitmap::kARGB_8888_Config:
-                    if (safeSize != 0x8E1BC9BF040000LL) {
+                    if (safeSize.as64() != 0x8E1BC9BF040000LL) {
                         sizeFail = true;
                     }
                     break;
@@ -381,7 +381,7 @@
             }
             if (sizeFail) {
                 SkString str;
-                str.printf("computeSafeSize64() wrong size: %s",
+                str.printf("getSafeSize64() wrong size: %s",
                     getSkConfigName(tstSafeSize));
                 reporter->reportFailed(str);
             }