Simple CL to add a joinWithPossiblyEmptyArg to SkRect

include/core/SkRect.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkRect_DEFINED
 #define SkRect_DEFINED
 
@@ skipping 729 matching lines @@
     void join(const SkRect& r) {
         this->join(r.fLeft, r.fTop, r.fRight, r.fBottom);
     }
 
     void joinNonEmptyArg(const SkRect& r) {
         SkASSERT(!r.isEmpty());
         // if we are empty, just assign
         if (fLeft >= fRight || fTop >= fBottom) {
             *this = r;
         } else {
-            fLeft   = SkMinScalar(fLeft, r.left());
-            fTop    = SkMinScalar(fTop, r.top());
-            fRight  = SkMaxScalar(fRight, r.right());
-            fBottom = SkMaxScalar(fBottom, r.bottom());
+            this->joinPossiblyEmptyRect(r);
         }
     }
 
     /**
+     * Joins the rectangle with another without checking if either are empty (may produce unexpected
+     * results if either rect is inverted).
+     */
+    void joinPossiblyEmptyRect(const SkRect& r) {
+        fLeft   = SkMinScalar(fLeft, r.left());
+        fTop    = SkMinScalar(fTop, r.top());
+        fRight  = SkMaxScalar(fRight, r.right());
+        fBottom = SkMaxScalar(fBottom, r.bottom());
+    }
+
+    /**
      *  Grow the rect to include the specified (x,y). After this call, the
      *  following will be true: fLeft <= x <= fRight && fTop <= y <= fBottom.
      *
      *  This is close, but not quite the same contract as contains(), since
      *  contains() treats the left and top different from the right and bottom.
      *  contains(x,y) -> fLeft <= x < fRight && fTop <= y < fBottom. Also note
      *  that contains(x,y) always returns false if the rect is empty.
      */
     void growToInclude(SkScalar x, SkScalar y) {
         fLeft  = SkMinScalar(x, fLeft);
@@ skipping 141 matching lines @@
     void dumpHex() const { this->dump(true); }
 };
 
 inline bool SkIRect::contains(const SkRect& r) const {
     return  !r.isEmpty() && !this->isEmpty() &&     // check for empties
             (SkScalar)fLeft <= r.fLeft && (SkScalar)fTop <= r.fTop &&
             (SkScalar)fRight >= r.fRight && (SkScalar)fBottom >= r.fBottom;
 }
 
 #endif