Define clear regions in terms of GrFixedClip

src/gpu/GrFixedClip.h

Index: src/gpu/GrFixedClip.h
diff --git a/src/gpu/GrFixedClip.h b/src/gpu/GrFixedClip.h
index 01498c11613429330606e833ce29cfb9ee6ac9dd..81fd90a3458aaa19f6b6350fca3d781e42fff0e8 100644
--- a/src/gpu/GrFixedClip.h
+++ b/src/gpu/GrFixedClip.h
@@ -12,39 +12,36 @@
 #include "GrTypesPriv.h"
 
 /**
- * GrFixedClip is a clip that can be represented by fixed-function hardware. It never modifies the
- * stencil buffer itself, but can be configured to use whatever clip is already there.
+ * GrFixedClip is a clip that gets implemented by fixed-function hardware.
  */
-class GrFixedClip final : public GrClip {
+class GrFixedClip : public GrClip {
 public:
-    GrFixedClip() : fHasStencilClip(false) {}
-    GrFixedClip(const SkIRect& scissorRect)
-        : fScissorState(scissorRect)
-        , fHasStencilClip(false) {}
-
-    void reset() {
-        fScissorState.setDisabled();
-        fHasStencilClip = false;
-    }
+    GrFixedClip() = default;
+    explicit GrFixedClip(const SkIRect& scissorRect) : fScissorState(scissorRect) {}
+
+    const GrScissorState& scissorState() const { return fScissorState; }
+    bool scissorEnabled() const { return fScissorState.enabled(); }
+    const SkIRect& scissorRect() const { SkASSERT(scissorEnabled()); return fScissorState.rect(); }
 
-    void reset(const SkIRect& scissorRect) {
-        fScissorState.set(scissorRect);
-        fHasStencilClip = false;
+    void disableScissor() { fScissorState.setDisabled(); }
+
+    bool SK_WARN_UNUSED_RESULT intersect(const SkIRect& irect) {
+        return fScissorState.intersect(irect);
     }
 
-    void enableStencilClip() { fHasStencilClip = true; }
-    void disableStencilClip() { fHasStencilClip = false; }
+    static const GrFixedClip& disabled();
 
-    bool quickContains(const SkRect&) const final;
+protected:
+    bool quickContains(const SkRect& rect) const override {
+        return !fScissorState.enabled() || GrClip::IsInsideClip(fScissorState.rect(), rect);
+    }
     void getConservativeBounds(int width, int height, SkIRect* devResult,
-                               bool* isIntersectionOfRects) const final;
-
-private:
+                               bool* isIntersectionOfRects) const override;
     bool apply(GrContext*, GrDrawContext*, bool useHWAA, bool hasUserStencilSettings,
-               GrAppliedClip* out) const final;
+               GrAppliedClip* out) const override;
 
+private:
     GrScissorState   fScissorState;
-    bool             fHasStencilClip;
 };
 
 #endif