Revert of Remove now-redundant SkPathOps enum. (patchset #1 id:1 of https://codereview.chromium.org/1051113005/)

Reason for revert:
Android is still using this. See 4c2968b94c/logs/build_error.log

Original issue's description:
> Remove now-redundant SkPathOps enum.
>
> R=caryclark,reed
> BUG=473772
>
> Committed: https://skia.googlesource.com/skia/+/143244e27d95255807d8fa505ce0affef96d1fc8

TBR=caryclark@google.com,reed@google.com,schenney@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=473772

Review URL: https://codereview.chromium.org/1068873002

include/pathops/SkPathOps.h

@@ -15,6 +15,11 @@ class SkPath;
 struct SkRect;
 
 
+// FIXME: remove this once the define in src/skia/SkUserConfig.h lands
+#ifndef SK_SUPPORT_LEGACY_PATHOP_ENUMS
+#define SK_SUPPORT_LEGACY_PATHOP_ENUMS
+#endif
+
 // FIXME: move everything below into the SkPath class
 /**
   *  The logical operations that can be performed when combining two paths.
@@ -25,6 +30,14 @@ enum SkPathOp {
     kUnion_SkPathOp,              //!< union (inclusive-or) the two paths
     kXOR_SkPathOp,                //!< exclusive-or the two paths
     kReverseDifference_SkPathOp,  //!< subtract the first path from the op path
+
+#ifdef SK_SUPPORT_LEGACY_PATHOP_ENUMS
+    kDifference_PathOp = 0,     //!< subtract the op path from the first path
+    kIntersect_PathOp,          //!< intersect the two paths
+    kUnion_PathOp,              //!< union (inclusive-or) the two paths
+    kXOR_PathOp,                //!< exclusive-or the two paths
+    kReverseDifference_PathOp,  //!< subtract the first path from the op path
+#endif
 };
 
 /** Set this path to the result of applying the Op to this path and the

src/utils/debugger/SkDebugCanvas.cpp

@@ -564,11 +564,11 @@ static const char* gFillTypeStrs[] = {
 };
 
 static const char* gOpStrs[] = {
-    "kDifference_SkPathOp",
-    "kIntersect_SkPathOp",
-    "kUnion_SkPathOp",
+    "kDifference_PathOp",
+    "kIntersect_PathOp",
+    "kUnion_PathOp",
     "kXor_PathOp",
-    "kReverseDifference_SkPathOp",
+    "kReverseDifference_PathOp",
 };
 
 static const char kHTML4SpaceIndent[] = "    ";