SkAdvancedTypefaceMetrics: fail cleanly.

BUG=567031
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1956753002

Review-Url: https://codereview.chromium.org/1956753002

diff --git a/src/core/SkAdvancedTypefaceMetrics.cpp b/src/core/SkAdvancedTypefaceMetrics.cpp
index 318f4a0..0e9ba95 100644 (file)
--- a/src/core/SkAdvancedTypefaceMetrics.cpp
+++ b/src/core/SkAdvancedTypefaceMetrics.cpp
@@ -257,6 +257,9 @@ SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* getAdvanceData(
     }
     if (curRange->fStartId == lastIndex) {
         SkASSERT(prevRange);
+        if (!prevRange) {
+            return nullptr;  // https://crbug.com/567031
+        }
         SkASSERT(prevRange->fNext->fStartId == lastIndex);
         prevRange->fNext.reset();
     } else {