Fix gpu dashing for case where all intervals are 0.

src/gpu/GrStrokeInfo.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrStrokeInfo.h"
 #include "GrResourceKey.h"
 #include "SkDashPathPriv.h"
 
+bool all_dash_intervals_zero(const SkScalar* intervals, int count) {
+    for (int i = 0 ; i < count; ++i) {
+        if (intervals[i] != 0) {
+            return false;
+        }
+    }
+    return true;
+}
+
 bool GrStrokeInfo::applyDashToPath(SkPath* dst, GrStrokeInfo* dstStrokeInfo,
                                    const SkPath& src) const {
     if (this->isDashed()) {
         SkPathEffect::DashInfo info;
         info.fIntervals = fIntervals.get();
         info.fCount = fIntervals.count();
         info.fPhase = fDashPhase;
         GrStrokeInfo filteredStroke(*this, false);
+        // Handle the case where all intervals are 0 and we simply drop the dash effect
+        if (all_dash_intervals_zero(fIntervals.get(), fIntervals.count())) {
+            *dstStrokeInfo = filteredStroke;
+            *dst = src;
+            return true;
+        }
+        // See if we can filter the dash into a path on cpu
         if (SkDashPath::FilterDashPath(dst, src, &filteredStroke, nullptr, info)) {
             *dstStrokeInfo = filteredStroke;
             return true;
         }
     }
     return false;
 }
 
 void GrStrokeInfo::asUniqueKeyFragment(uint32_t* data) const {
     const int kSkScalarData32Cnt = sizeof(SkScalar) / sizeof(uint32_t);
@@ skipping 39 matching lines @@
         const SkScalar* intervals = this->getDashIntervals();
         int intervalByteCnt = count * sizeof(SkScalar);
         memcpy(&data[i], intervals, intervalByteCnt);
         // Enable the line below if fields are added after dashing.
         SkDEBUGCODE(i += kSkScalarData32Cnt * count);
     }
 
     SkASSERT(this->computeUniqueKeyFragmentData32Cnt() == i);
 }