abstract name of clipping ops, to transtion to a more restricted set

SkRegion::Op --> SkCanvas::ClipOp (alias) --> SkClipOp

pre-CL needed in chrome : https://codereview.chromium.org/2355583002/

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2355483002

Review-Url: https://codereview.chromium.org/2355483002
diff --git a/tools/debugger/SkDebugCanvas.cpp b/tools/debugger/SkDebugCanvas.cpp
index 4c633ab..f15c68c 100644
--- a/tools/debugger/SkDebugCanvas.cpp
+++ b/tools/debugger/SkDebugCanvas.cpp
@@ -107,7 +107,7 @@
     SkASSERT(!large.roundOut().isEmpty());
 #endif
     // call the base class' version to avoid adding a draw command
-    this->INHERITED::onClipRect(large, SkRegion::kReplace_Op, kHard_ClipEdgeStyle);
+    this->INHERITED::onClipRect(large, kReplace_Op, kHard_ClipEdgeStyle);
 }
 
 SkDebugCanvas::~SkDebugCanvas() {
@@ -155,21 +155,21 @@
 public:
     SkDebugClipVisitor(SkCanvas* canvas) : fCanvas(canvas) {}
 
-    void clipRect(const SkRect& r, SkRegion::Op, bool doAA) override {
+    void clipRect(const SkRect& r, SkCanvas::ClipOp, bool doAA) override {
         SkPaint p;
         p.setColor(SK_ColorRED);
         p.setStyle(SkPaint::kStroke_Style);
         p.setAntiAlias(doAA);
         fCanvas->drawRect(r, p);
     }
-    void clipRRect(const SkRRect& rr, SkRegion::Op, bool doAA) override {
+    void clipRRect(const SkRRect& rr, SkCanvas::ClipOp, bool doAA) override {
         SkPaint p;
         p.setColor(SK_ColorGREEN);
         p.setStyle(SkPaint::kStroke_Style);
         p.setAntiAlias(doAA);
         fCanvas->drawRRect(rr, p);
     }
-    void clipPath(const SkPath& path, SkRegion::Op, bool doAA) override {
+    void clipPath(const SkPath& path, SkCanvas::ClipOp, bool doAA) override {
         SkPaint p;
         p.setColor(SK_ColorBLUE);
         p.setStyle(SkPaint::kStroke_Style);
@@ -222,7 +222,7 @@
     canvas->clear(SK_ColorWHITE);
     canvas->resetMatrix();
     if (!windowRect.isEmpty()) {
-        canvas->clipRect(windowRect, SkRegion::kReplace_Op);
+        canvas->clipRect(windowRect, SkCanvas::kReplace_Op);
     }
     this->applyUserTransform(canvas);
 
@@ -284,7 +284,7 @@
         canvas->save();
         #define LARGE_COORD 1000000000
         canvas->clipRect(SkRect::MakeLTRB(-LARGE_COORD, -LARGE_COORD, LARGE_COORD, LARGE_COORD),
-                       SkRegion::kReverseDifference_Op);
+                       SkCanvas::kReverseDifference_Op);
         SkPaint clipPaint;
         clipPaint.setColor(fClipVizColor);
         canvas->drawPaint(clipPaint);
@@ -299,7 +299,7 @@
         if (!windowRect.isEmpty()) {
             SkRect r = windowRect;
             r.outset(SK_Scalar1, SK_Scalar1);
-            canvas->clipRect(r, SkRegion::kReplace_Op);
+            canvas->clipRect(r, SkCanvas::kReplace_Op);
         }
         // visualize existing clips
         SkDebugClipVisitor visitor(canvas);
@@ -320,9 +320,9 @@
             if (type != SkClipStack::Element::kEmpty_Type) {
                element->asPath(&operand);
             }
-            SkRegion::Op elementOp = element->getOp();
+            SkCanvas::ClipOp elementOp = element->getOp();
             this->addClipStackData(devPath, operand, elementOp);
-            if (elementOp == SkRegion::kReplace_Op) {
+            if (elementOp == SkCanvas::kReplace_Op) {
                 devPath = operand;
             } else {
                 Op(devPath, operand, (SkPathOp) elementOp, &devPath);
@@ -543,19 +543,19 @@
     this->updatePaintFilterCanvas();
 }
 
-void SkDebugCanvas::onClipPath(const SkPath& path, SkRegion::Op op, ClipEdgeStyle edgeStyle) {
+void SkDebugCanvas::onClipPath(const SkPath& path, ClipOp op, ClipEdgeStyle edgeStyle) {
     this->addDrawCommand(new SkClipPathCommand(path, op, kSoft_ClipEdgeStyle == edgeStyle));
 }
 
-void SkDebugCanvas::onClipRect(const SkRect& rect, SkRegion::Op op, ClipEdgeStyle edgeStyle) {
+void SkDebugCanvas::onClipRect(const SkRect& rect, ClipOp op, ClipEdgeStyle edgeStyle) {
     this->addDrawCommand(new SkClipRectCommand(rect, op, kSoft_ClipEdgeStyle == edgeStyle));
 }
 
-void SkDebugCanvas::onClipRRect(const SkRRect& rrect, SkRegion::Op op, ClipEdgeStyle edgeStyle) {
+void SkDebugCanvas::onClipRRect(const SkRRect& rrect, ClipOp op, ClipEdgeStyle edgeStyle) {
     this->addDrawCommand(new SkClipRRectCommand(rrect, op, kSoft_ClipEdgeStyle == edgeStyle));
 }
 
-void SkDebugCanvas::onClipRegion(const SkRegion& region, SkRegion::Op op) {
+void SkDebugCanvas::onClipRegion(const SkRegion& region, ClipOp op) {
     this->addDrawCommand(new SkClipRegionCommand(region, op));
 }
 
@@ -828,8 +828,8 @@
 }
 
 void SkDebugCanvas::addClipStackData(const SkPath& devPath, const SkPath& operand,
-                                     SkRegion::Op elementOp) {
-    if (elementOp == SkRegion::kReplace_Op) {
+                                     SkCanvas::ClipOp elementOp) {
+    if (elementOp == SkCanvas::kReplace_Op) {
         if (!lastClipStackData(devPath)) {
             fSaveDevPath = operand;
         }
diff --git a/tools/debugger/SkDebugCanvas.h b/tools/debugger/SkDebugCanvas.h
index 6a3d925..5d00799 100644
--- a/tools/debugger/SkDebugCanvas.h
+++ b/tools/debugger/SkDebugCanvas.h
@@ -248,10 +248,10 @@
                          const SkPaint*, SrcRectConstraint) override;
     void onDrawBitmapNine(const SkBitmap&, const SkIRect& center, const SkRect& dst,
                           const SkPaint*) override;
-    void onClipRect(const SkRect&, SkRegion::Op, ClipEdgeStyle) override;
-    void onClipRRect(const SkRRect&, SkRegion::Op, ClipEdgeStyle) override;
-    void onClipPath(const SkPath&, SkRegion::Op, ClipEdgeStyle) override;
-    void onClipRegion(const SkRegion& region, SkRegion::Op) override;
+    void onClipRect(const SkRect&, ClipOp, ClipEdgeStyle) override;
+    void onClipRRect(const SkRRect&, ClipOp, ClipEdgeStyle) override;
+    void onClipPath(const SkPath&, ClipOp, ClipEdgeStyle) override;
+    void onClipRegion(const SkRegion& region, ClipOp) override;
 
     void onDrawPicture(const SkPicture*, const SkMatrix*, const SkPaint*) override;
 
@@ -310,7 +310,7 @@
 
     void resetClipStackData() { fClipStackData.reset(); fCalledAddStackData = false; }
 
-    void addClipStackData(const SkPath& devPath, const SkPath& operand, SkRegion::Op elementOp);
+    void addClipStackData(const SkPath& devPath, const SkPath& operand, ClipOp elementOp);
     void addPathData(const SkPath& path, const char* pathName);
     bool lastClipStackData(const SkPath& devPath);
     void outputConicPoints(const SkPoint* pts, SkScalar weight);
diff --git a/tools/debugger/SkDrawCommand.cpp b/tools/debugger/SkDrawCommand.cpp
index 75978d4..35e9201 100644
--- a/tools/debugger/SkDrawCommand.cpp
+++ b/tools/debugger/SkDrawCommand.cpp
@@ -573,19 +573,19 @@
     return Json::Value("<unimplemented>");
 }
 
-static Json::Value make_json_regionop(SkRegion::Op op) {
+static Json::Value make_json_regionop(SkCanvas::ClipOp op) {
     switch (op) {
-        case SkRegion::kDifference_Op:
+        case SkCanvas::kDifference_Op:
             return Json::Value(SKDEBUGCANVAS_REGIONOP_DIFFERENCE);
-        case SkRegion::kIntersect_Op:
+        case SkCanvas::kIntersect_Op:
             return Json::Value(SKDEBUGCANVAS_REGIONOP_INTERSECT);
-        case SkRegion::kUnion_Op:
+        case SkCanvas::kUnion_Op:
             return Json::Value(SKDEBUGCANVAS_REGIONOP_UNION);
-        case SkRegion::kXOR_Op:
+        case SkCanvas::kXOR_Op:
             return Json::Value(SKDEBUGCANVAS_REGIONOP_XOR);
-        case SkRegion::kReverseDifference_Op:
+        case SkCanvas::kReverseDifference_Op:
             return Json::Value(SKDEBUGCANVAS_REGIONOP_REVERSE_DIFFERENCE);
-        case SkRegion::kReplace_Op:
+        case SkCanvas::kReplace_Op:
             return Json::Value(SKDEBUGCANVAS_REGIONOP_REPLACE);
         default:
             SkASSERT(false);
@@ -1605,28 +1605,28 @@
     }
 }
 
-SkRegion::Op get_json_regionop(Json::Value& jsonOp) {
+SkCanvas::ClipOp get_json_clipop(Json::Value& jsonOp) {
     const char* op = jsonOp.asCString();
     if (!strcmp(op, SKDEBUGCANVAS_REGIONOP_DIFFERENCE)) {
-        return SkRegion::kDifference_Op;
+        return SkCanvas::kDifference_Op;
     }
     else if (!strcmp(op, SKDEBUGCANVAS_REGIONOP_INTERSECT)) {
-        return SkRegion::kIntersect_Op;
+        return SkCanvas::kIntersect_Op;
     }
     else if (!strcmp(op, SKDEBUGCANVAS_REGIONOP_UNION)) {
-        return SkRegion::kUnion_Op;
+        return SkCanvas::kUnion_Op;
     }
     else if (!strcmp(op, SKDEBUGCANVAS_REGIONOP_XOR)) {
-        return SkRegion::kXOR_Op;
+        return SkCanvas::kXOR_Op;
     }
     else if (!strcmp(op, SKDEBUGCANVAS_REGIONOP_REVERSE_DIFFERENCE)) {
-        return SkRegion::kReverseDifference_Op;
+        return SkCanvas::kReverseDifference_Op;
     }
     else if (!strcmp(op, SKDEBUGCANVAS_REGIONOP_REPLACE)) {
-        return SkRegion::kReplace_Op;
+        return SkCanvas::kReplace_Op;
     }
     SkASSERT(false);
-    return SkRegion::kIntersect_Op;
+    return SkCanvas::kIntersect_Op;
 }
 
 SkClearCommand::SkClearCommand(SkColor color) : INHERITED(kDrawClear_OpType) {
@@ -1649,14 +1649,14 @@
     return new SkClearCommand(get_json_color(color));
 }
 
-SkClipPathCommand::SkClipPathCommand(const SkPath& path, SkRegion::Op op, bool doAA)
+SkClipPathCommand::SkClipPathCommand(const SkPath& path, SkCanvas::ClipOp op, bool doAA)
     : INHERITED(kClipPath_OpType) {
     fPath = path;
     fOp = op;
     fDoAA = doAA;
 
     fInfo.push(SkObjectParser::PathToString(path));
-    fInfo.push(SkObjectParser::RegionOpToString(op));
+    fInfo.push(SkObjectParser::ClipOpToString(op));
     fInfo.push(SkObjectParser::BoolToString(doAA));
 }
 
@@ -1681,17 +1681,17 @@
                                                UrlDataManager& urlDataManager) {
     SkPath path;
     extract_json_path(command[SKDEBUGCANVAS_ATTRIBUTE_PATH], &path);
-    return new SkClipPathCommand(path, get_json_regionop(command[SKDEBUGCANVAS_ATTRIBUTE_REGIONOP]),
+    return new SkClipPathCommand(path, get_json_clipop(command[SKDEBUGCANVAS_ATTRIBUTE_REGIONOP]),
                                  command[SKDEBUGCANVAS_ATTRIBUTE_ANTIALIAS].asBool());
 }
 
-SkClipRegionCommand::SkClipRegionCommand(const SkRegion& region, SkRegion::Op op)
+SkClipRegionCommand::SkClipRegionCommand(const SkRegion& region, SkCanvas::ClipOp op)
     : INHERITED(kClipRegion_OpType) {
     fRegion = region;
     fOp = op;
 
     fInfo.push(SkObjectParser::RegionToString(region));
-    fInfo.push(SkObjectParser::RegionOpToString(op));
+    fInfo.push(SkObjectParser::ClipOpToString(op));
 }
 
 void SkClipRegionCommand::execute(SkCanvas* canvas) const {
@@ -1711,14 +1711,14 @@
     return nullptr;
 }
 
-SkClipRectCommand::SkClipRectCommand(const SkRect& rect, SkRegion::Op op, bool doAA)
+SkClipRectCommand::SkClipRectCommand(const SkRect& rect, SkCanvas::ClipOp op, bool doAA)
     : INHERITED(kClipRect_OpType) {
     fRect = rect;
     fOp = op;
     fDoAA = doAA;
 
     fInfo.push(SkObjectParser::RectToString(rect));
-    fInfo.push(SkObjectParser::RegionOpToString(op));
+    fInfo.push(SkObjectParser::ClipOpToString(op));
     fInfo.push(SkObjectParser::BoolToString(doAA));
 }
 
@@ -1742,18 +1742,18 @@
                                                UrlDataManager& urlDataManager) {
     SkRect rect;
     extract_json_rect(command[SKDEBUGCANVAS_ATTRIBUTE_COORDS], &rect);
-    return new SkClipRectCommand(rect, get_json_regionop(command[SKDEBUGCANVAS_ATTRIBUTE_REGIONOP]),
+    return new SkClipRectCommand(rect, get_json_clipop(command[SKDEBUGCANVAS_ATTRIBUTE_REGIONOP]),
                                  command[SKDEBUGCANVAS_ATTRIBUTE_ANTIALIAS].asBool());
 }
 
-SkClipRRectCommand::SkClipRRectCommand(const SkRRect& rrect, SkRegion::Op op, bool doAA)
+SkClipRRectCommand::SkClipRRectCommand(const SkRRect& rrect, SkCanvas::ClipOp op, bool doAA)
     : INHERITED(kClipRRect_OpType) {
     fRRect = rrect;
     fOp = op;
     fDoAA = doAA;
 
     fInfo.push(SkObjectParser::RRectToString(rrect));
-    fInfo.push(SkObjectParser::RegionOpToString(op));
+    fInfo.push(SkObjectParser::ClipOpToString(op));
     fInfo.push(SkObjectParser::BoolToString(doAA));
 }
 
@@ -1779,7 +1779,7 @@
     SkRRect rrect;
     extract_json_rrect(command[SKDEBUGCANVAS_ATTRIBUTE_COORDS], &rrect);
     return new SkClipRRectCommand(rrect,
-                                  get_json_regionop(command[SKDEBUGCANVAS_ATTRIBUTE_REGIONOP]),
+                                  get_json_clipop(command[SKDEBUGCANVAS_ATTRIBUTE_REGIONOP]),
                                   command[SKDEBUGCANVAS_ATTRIBUTE_ANTIALIAS].asBool());
 }
 
diff --git a/tools/debugger/SkDrawCommand.h b/tools/debugger/SkDrawCommand.h
index 07dd477..27b56e2 100644
--- a/tools/debugger/SkDrawCommand.h
+++ b/tools/debugger/SkDrawCommand.h
@@ -174,69 +174,69 @@
 
 class SkClipPathCommand : public SkDrawCommand {
 public:
-    SkClipPathCommand(const SkPath& path, SkRegion::Op op, bool doAA);
+    SkClipPathCommand(const SkPath& path, SkCanvas::ClipOp op, bool doAA);
     void execute(SkCanvas* canvas) const override;
     bool render(SkCanvas* canvas) const override;
     Json::Value toJSON(UrlDataManager& urlDataManager) const override;
     static SkClipPathCommand* fromJSON(Json::Value& command, UrlDataManager& urlDataManager);
 
 private:
-    SkPath       fPath;
-    SkRegion::Op fOp;
-    bool         fDoAA;
+    SkPath           fPath;
+    SkCanvas::ClipOp fOp;
+    bool             fDoAA;
 
     typedef SkDrawCommand INHERITED;
 };
 
 class SkClipRegionCommand : public SkDrawCommand {
 public:
-    SkClipRegionCommand(const SkRegion& region, SkRegion::Op op);
+    SkClipRegionCommand(const SkRegion& region, SkCanvas::ClipOp op);
     void execute(SkCanvas* canvas) const override;
     Json::Value toJSON(UrlDataManager& urlDataManager) const override;
     static SkClipRegionCommand* fromJSON(Json::Value& command, UrlDataManager& urlDataManager);
 
 private:
-    SkRegion     fRegion;
-    SkRegion::Op fOp;
+    SkRegion         fRegion;
+    SkCanvas::ClipOp fOp;
 
     typedef SkDrawCommand INHERITED;
 };
 
 class SkClipRectCommand : public SkDrawCommand {
 public:
-    SkClipRectCommand(const SkRect& rect, SkRegion::Op op, bool doAA);
+    SkClipRectCommand(const SkRect& rect, SkCanvas::ClipOp op, bool doAA);
     void execute(SkCanvas* canvas) const override;
     Json::Value toJSON(UrlDataManager& urlDataManager) const override;
     static SkClipRectCommand* fromJSON(Json::Value& command, UrlDataManager& urlDataManager);
 
     const SkRect& rect() const { return fRect; }
-    SkRegion::Op op() const { return fOp; }
+    SkCanvas::ClipOp op() const { return fOp; }
     bool doAA() const { return fDoAA; }
 
 private:
-    SkRect       fRect;
-    SkRegion::Op fOp;
-    bool         fDoAA;
+    SkRect           fRect;
+    SkCanvas::ClipOp fOp;
+    bool             fDoAA;
 
     typedef SkDrawCommand INHERITED;
 };
 
 class SkClipRRectCommand : public SkDrawCommand {
 public:
-    SkClipRRectCommand(const SkRRect& rrect, SkRegion::Op op, bool doAA);
+    SkClipRRectCommand(const SkRRect& rrect, SkCanvas::ClipOp op, bool doAA);
     void execute(SkCanvas* canvas) const override;
     bool render(SkCanvas* canvas) const override;
     Json::Value toJSON(UrlDataManager& urlDataManager) const override;
     static SkClipRRectCommand* fromJSON(Json::Value& command, UrlDataManager& urlDataManager);
 
     const SkRRect& rrect() const { return fRRect; }
-    SkRegion::Op op() const { return fOp; }
+    SkCanvas::ClipOp op() const { return fOp; }
     bool doAA() const { return fDoAA; }
 
 private:
-    SkRRect      fRRect;
-    SkRegion::Op fOp;
-    bool         fDoAA;
+    SkRRect          fRRect;
+    SkCanvas::ClipOp fOp;
+    bool             fDoAA;
 
     typedef SkDrawCommand INHERITED;
 };
diff --git a/tools/debugger/SkObjectParser.cpp b/tools/debugger/SkObjectParser.cpp
index 3642783..5f0e5f8 100644
--- a/tools/debugger/SkObjectParser.cpp
+++ b/tools/debugger/SkObjectParser.cpp
@@ -313,19 +313,19 @@
     return mRRect;
 }
 
-SkString* SkObjectParser::RegionOpToString(SkRegion::Op op) {
+SkString* SkObjectParser::ClipOpToString(SkCanvas::ClipOp op) {
     SkString* mOp = new SkString("SkRegion::Op: ");
-    if (op == SkRegion::kDifference_Op) {
+    if (op == SkCanvas::kDifference_Op) {
         mOp->append("kDifference_Op");
-    } else if (op == SkRegion::kIntersect_Op) {
+    } else if (op == SkCanvas::kIntersect_Op) {
         mOp->append("kIntersect_Op");
-    } else if (op == SkRegion::kUnion_Op) {
+    } else if (op == SkCanvas::kUnion_Op) {
         mOp->append("kUnion_Op");
-    } else if (op == SkRegion::kXOR_Op) {
+    } else if (op == SkCanvas::kXOR_Op) {
         mOp->append("kXOR_Op");
-    } else if (op == SkRegion::kReverseDifference_Op) {
+    } else if (op == SkCanvas::kReverseDifference_Op) {
         mOp->append("kReverseDifference_Op");
-    } else if (op == SkRegion::kReplace_Op) {
+    } else if (op == SkCanvas::kReplace_Op) {
         mOp->append("kReplace_Op");
     } else {
         mOp->append("Unknown Type");
diff --git a/tools/debugger/SkObjectParser.h b/tools/debugger/SkObjectParser.h
index 9bdfad5..11baf12 100644
--- a/tools/debugger/SkObjectParser.h
+++ b/tools/debugger/SkObjectParser.h
@@ -101,7 +101,7 @@
         Returns a string representation of the SkRegion enum.
         @param op  SkRegion::op enum
      */
-    static SkString* RegionOpToString(SkRegion::Op op);
+    static SkString* ClipOpToString(SkCanvas::ClipOp op);
 
     /**
         Returns a string representation of the SkRegion.