Don't allow iteration through non-finite points.

Added a unit test too.

BUG=chromium:756563

Change-Id: Ic77a89b4a98d1a553877af9807a3d3bdcd077bb9
Reviewed-on: https://skia-review.googlesource.com/44420
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Reed <reed@google.com>

include/private/SkPathRef.h

@@ -124,6 +124,8 @@ public:
         /** Return the next verb in this iteration of the path. When all
             segments have been visited, return kDone_Verb.
 
+            If any point in the path is non-finite, return kDone_Verb immediately.
+
             @param  pts The points representing the current verb and/or segment
                         This must not be NULL.
             @return The verb for the current segment

src/core/SkPathRef.cpp

@@ -298,7 +298,7 @@ SkPathRef* SkPathRef::CreateFromBuffer(SkRBuffer* buffer) {
             return nullptr;
         }
     }
-    
+
     ref->fBoundsIsDirty = false;
 
     // resetToSize clears fSegmentMask and fIsOval
@@ -691,6 +691,11 @@ void SkPathRef::Iter::setPathRef(const SkPathRef& path) {
     if (fConicWeights) {
       fConicWeights -= 1;  // begin one behind
     }
+
+    // Don't allow iteration through non-finite points.
+    if (!path.isFinite()) {
+        fVerbStop = fVerbs;
+    }
 }
 
 uint8_t SkPathRef::Iter::next(SkPoint pts[4]) {

tests/PathTest.cpp

@@ -4911,3 +4911,18 @@ DEF_TEST(PathRefSerialization, reporter) {
         REPORTER_ASSERT(reporter, !bytesRead);
     }
 }
+
+DEF_TEST(NonFinitePathIteration, reporter) {
+    SkPath path;
+    path.moveTo(SK_ScalarInfinity, SK_ScalarInfinity);
+
+    int verbs = 0;
+
+    SkPath::RawIter iter(path);
+    SkPoint         pts[4];
+    while (iter.next(pts) != SkPath::kDone_Verb) {
+        verbs++;
+    }
+
+    REPORTER_ASSERT(reporter, verbs == 0);
+}