Add asADash entry point into SkPathEffect to allow extracting Dash info from PathEffects

include/core/SkPathEffect.h

Index: include/core/SkPathEffect.h
diff --git a/include/core/SkPathEffect.h b/include/core/SkPathEffect.h
index 86ccf86a9223eedb59dfb7361102bfb067177868..9ccedc39739e77ca088ef0afbe5d4b16eae5f00c 100644
--- a/include/core/SkPathEffect.h
+++ b/include/core/SkPathEffect.h
@@ -104,6 +104,42 @@ public:
                           const SkStrokeRec&, const SkMatrix&,
                           const SkRect* cullR) const;
 
+    /**
+     *  If the PathEffect is a DashedPath effect asADash will return TwoInterval if there is a
+     *  single on and a single off interval. If there are additional intervals in the dash then
+     *  it will return Other. If a non NULL info is passed in the various DashInfo will be filled

[reed1, 2014/03/27 15:56:07]

s/Other/MultipleInterval

+     *  in if the PathEffect is a DashedPathEffect. If passed in info has an fCount equal or
+     *  greater to that of the effect, it will memcpy the values of fIntervals into the info.
+     *  Thus the general approach will be call asADash once with default info to get DashType
+     *  and fCount. If it is a DashPathEffect, allocate space for the intervals in info, then call
+     *  asAGradient again with the same info and fIntervals will get copied in.
+     *
+     *  None:
+     *      info is ignored.
+     *  TwoInterval:
+     *      uses all info.
+     *  MultipleInterval:
+     *      uses all info.
+     */
+
+    enum DashType {
+        kNone_DashType,
+        kTwoInterval_DashType,
+        kMultipleInterval_DashType,
+    };
+
+    struct DashInfo {
+        SkScalar*   fIntervals;         //!< Length of on/off intervals for dashed lines
+                                        //   Even values represent ons, and odds offs
+        int32_t     fCount;             //!< Number of intervals in the dash. Should be even number
+        SkScalar    fInitialDashLength; //!< Length of possibly shortened initial interval
+        int32_t     fInitialDashIndex;  //!< Which interval in fIntervals are we starting at
+        SkScalar    fIntervalLength;    //!< Length of all intervals
+        bool        fScaleToFit;
+    };
+
+    virtual DashType asADash(DashInfo* info) const;
+
     SK_DEFINE_FLATTENABLE_TYPE(SkPathEffect)
 
 protected: