Fill SkRRect::fType proactively.

I found no external mentions of SkRRect::kUnknown_Type.

Motivating race found by TSAN:
http://build.chromium.org/p/client.skia/builders/Test-Ubuntu13.10-GCE-NoGPU-x86_64-Release-TSAN-Trybot/builds/48/steps/dm/logs/stdio

BUG=skia:

Review URL: https://codereview.chromium.org/801693003

include/core/SkRRect.h

@@ -52,9 +52,6 @@ public:
      * by type(). The subtypes become progressively less restrictive.
      */
     enum Type {
-        // !< Internal indicator that the sub type must be computed.
-        kUnknown_Type = -1,
-
         // !< The RR is empty
         kEmpty_Type,
 
@@ -90,11 +87,6 @@ public:
      */
     Type getType() const {
         SkDEBUGCODE(this->validate();)
-
-        if (kUnknown_Type == fType) {
-            this->computeType();
-        }
-        SkASSERT(kUnknown_Type != fType);
         return static_cast<Type>(fType);
     }
 
@@ -301,11 +293,11 @@ private:
     // Radii order is UL, UR, LR, LL. Use Corner enum to index into fRadii[]
     SkVector fRadii[4];
     // use an explicitly sized type so we're sure the class is dense (no uninitialized bytes)
-    mutable int32_t fType;
+    int32_t fType;
     // TODO: add padding so we can use memcpy for flattening and not copy
     // uninitialized data
 
-    void computeType() const;
+    void computeType();
     bool checkCornerContainment(SkScalar x, SkScalar y) const;
 
     // to access fRadii directly

src/core/SkRRect.cpp

@@ -206,10 +206,8 @@ void SkRRect::setRectRadii(const SkRect& rect, const SkVector radii[4]) {
     fRadii[3].fX = clamp_radius_add(fRadii[3].fX, rect.fLeft, rect.fRight);
     fRadii[3].fY = clamp_radius_sub(fRadii[3].fY, rect.fTop, rect.fBottom);
 
-    // At this point we're either oval, simple, or complex (not empty or rect)
-    // but we lazily resolve the type to avoid the work if the information
-    // isn't required.
-    fType = (SkRRect::Type) kUnknown_Type;
+    // At this point we're either oval, simple, or complex (not empty or rect).
+    this->computeType();
 
     SkDEBUGCODE(this->validate();)
 }
@@ -305,8 +303,12 @@ static bool radii_are_nine_patch(const SkVector radii[4]) {
 }
 
 // There is a simplified version of this method in setRectXY
-void SkRRect::computeType() const {
-    SkDEBUGCODE(this->validate();)
+void SkRRect::computeType() {
+    struct Validator {
+        Validator(const SkRRect* r) : fR(r) {}
+        ~Validator() { SkDEBUGCODE(fR->validate();) }
+        const SkRRect* fR;
+    } autoValidate(this);
 
     if (fRect.isEmpty()) {
         fType = kEmpty_Type;
@@ -564,9 +566,6 @@ void SkRRect::validate() const {
             SkASSERT(!allRadiiZero && !allRadiiSame && !allCornersSquare);
             SkASSERT(!patchesOfNine);
             break;
-        case kUnknown_Type:
-            // no limits on this
-            break;
     }
 }
 #endif // SK_DEBUG

src/effects/SkBlurMaskFilter.cpp

@@ -324,10 +324,6 @@ SkBlurMaskFilterImpl::filterRRectToNine(const SkRRect& rrect, const SkMatrix& ma
                                         NinePatch* patch) const {
     SkASSERT(patch != NULL);
     switch (rrect.getType()) {
-        case SkRRect::kUnknown_Type:
-            // Unknown should never be returned.
-            SkASSERT(false);
-            // Fall through.
         case SkRRect::kEmpty_Type:
             // Nothing to draw.
             return kFalse_FilterReturn;

src/utils/SkLua.cpp

@@ -187,7 +187,7 @@ static SkScalar lua2scalar_def(lua_State* L, int index, SkScalar defaultValue) {
 static SkScalar getarray_scalar(lua_State* L, int stackIndex, int arrayIndex) {
     SkASSERT(lua_istable(L, stackIndex));
     lua_rawgeti(L, stackIndex, arrayIndex);
-    
+
     SkScalar value = lua2scalar(L, -1);
     lua_pop(L, 1);
     return value;
@@ -404,7 +404,7 @@ static SkScalar getfield_scalar(lua_State* L, int index, const char key[]) {
     SkASSERT(lua_istable(L, index));
     lua_pushstring(L, key);
     lua_gettable(L, index);
-    
+
     SkScalar value = lua2scalar(L, -1);
     lua_pop(L, 1);
     return value;
@@ -533,7 +533,7 @@ static int lcanvas_drawImageRect(lua_State* L) {
         srcRPtr = lua2rect(L, 3, &srcR);
     }
     lua2rect(L, 4, &dstR);
-    
+
     SkPaint paint;
     canvas->drawImageRect(image, srcRPtr, dstR, lua2OptionalPaint(L, 5, &paint));
     return 0;
@@ -1579,7 +1579,6 @@ static const struct luaL_Reg gSkPath_Methods[] = {
 
 static const char* rrect_type(const SkRRect& rr) {
     switch (rr.getType()) {
-        case SkRRect::kUnknown_Type: return "unknown";
         case SkRRect::kEmpty_Type: return "empty";
         case SkRRect::kRect_Type: return "rect";
         case SkRRect::kOval_Type: return "oval";