Add check for bad dash interval in dash effect picture read

src/effects/SkDashPathEffect.cpp

Index: src/effects/SkDashPathEffect.cpp
diff --git a/src/effects/SkDashPathEffect.cpp b/src/effects/SkDashPathEffect.cpp
index 24361bd3697bbbc686f4267c149202507e9d4191..f6c7caecd94ee458eb2a0ff76bbc86bd304c0b68 100644
--- a/src/effects/SkDashPathEffect.cpp
+++ b/src/effects/SkDashPathEffect.cpp
@@ -565,10 +565,12 @@ SkDashPathEffect::SkDashPathEffect(SkReadBuffer& buffer) : INHERITED(buffer) {
 
     if (useOldPic) {
         fPhase = 0;
-        for (int i = 0; i < fInitialDashIndex; ++i) {
-            fPhase += fIntervals[i];
+        if (fInitialDashLength != -1) { // Signal for bad dash interval
+            for (int i = 0; i < fInitialDashIndex; ++i) {
+                fPhase += fIntervals[i];
+            }
+            fPhase += fIntervals[fInitialDashIndex] - fInitialDashLength;
         }
-        fPhase += fIntervals[fInitialDashIndex] - fInitialDashLength;
     } else {
         this->setInternalMembers(fPhase);
     }