Initial error handling code

include/core/SkRect.h

Index: include/core/SkRect.h
diff --git a/include/core/SkRect.h b/include/core/SkRect.h
index d8919ae5d6b888d3195cc57ce7346bc905cf2a8c..bd5d026d5067de4fbf28e1c37ebaea8d518370a5 100644
--- a/include/core/SkRect.h
+++ b/include/core/SkRect.h
@@ -100,6 +100,8 @@ struct SK_API SkIRect {
      */
     bool isEmpty() const { return fLeft >= fRight || fTop >= fBottom; }

[reed1, 2013/09/05 19:06:39]

Separate note: given our recent realization about overflow even in ints, perhaps
we should change isEmpty and isInverted...

isEmpty : return fRight - fLeft <= 0
isInverted : return fRight - fLeft < 0

We can think about that after this CL, just wanted to mention it.

 
+    bool isInverted() const { return fLeft > fRight || fTop > fBottom; }
+
     bool isLargest() const { return SK_MinS32 == fLeft &&
                                     SK_MinS32 == fTop &&
                                     SK_MaxS32 == fRight &&
@@ -419,6 +421,8 @@ struct SK_API SkRect {
      */
     bool isEmpty() const { return fLeft >= fRight || fTop >= fBottom; }
 
+    bool isInverted() const { return fLeft > fRight || fTop > fBottom; }
+
     /**
      *  Returns true iff all values in the rect are finite. If any are
      *  infinite or NaN (or SK_FixedNaN when SkScalar is fixed) then this