Revert "Revert "SkRegion: more robust validation""

This reverts commit 7f4124058eda42e8379f2e979fabc339b8580348.

Original change's description:
> Revert "SkRegion: more robust validation"
> 
> This reverts commit 711450e948b9900011dc0d474f82bf7bc9913259.
> 
> Reason for revert: speculative revert to fix chrome roll.
> 
> Original change's description:
> > SkRegion: more robust validation
> > 
> > BUG=oss-fuzz:1864
> > Change-Id: I4c3d3c4c7b0717399fe16f227e032682b13ebc74
> > Reviewed-on: https://skia-review.googlesource.com/20322
> > Reviewed-by: Cary Clark <caryclark@google.com>
> > Commit-Queue: Hal Canary <halcanary@google.com>

TBR=halcanary@google.com,caryclark@google.com,reed@google.com

Change-Id: I1e5500cb83adeeda544282577ce55812e1b5d682
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: oss-fuzz:1864
Reviewed-on: https://skia-review.googlesource.com/20501
Reviewed-by: Hal Canary <halcanary@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/tests/RegionTest.cpp b/tests/RegionTest.cpp
index 2a5d0a5059..7fcf1014f7 100644
--- a/tests/RegionTest.cpp
+++ b/tests/RegionTest.cpp
@@ -328,6 +328,13 @@ DEF_TEST(Region_readFromMemory_bad, r) {
         REPORTER_ASSERT(r, 0 != region.readFromMemory(data, sizeof(data)));
     }
     {
+        // Example of valid data with 4 intervals
+        int32_t data[] = {19, 0, 0, 30, 30, 3, 4, 0, 10, 2, 0, 10, 20, 30,
+                          2147483647, 20, 0, 2147483647, 30, 2, 0, 10, 20, 30,
+                          2147483647, 2147483647};
+        REPORTER_ASSERT(r, 0 != region.readFromMemory(data, sizeof(data)));
+    }
+    {
         // Short count
         int32_t data[] = {8, 0, 0, 10, 10, 1, 2, 0, 10, 2, 0, 4, 6, 10,
                           2147483647, 2147483647};
@@ -363,4 +370,29 @@ DEF_TEST(Region_readFromMemory_bad, r) {
                           -1, 2147483647};
         REPORTER_ASSERT(r, 0 == region.readFromMemory(data, sizeof(data)));
     }
+    {
+        // starts with empty yspan
+        int32_t data[] = {12, 0, 0, 10, 10, 2, 2, -5, 0, 0, 2147483647, 10,
+                          2, 0, 4, 6, 10, 2147483647, 2147483647};
+        REPORTER_ASSERT(r, 0 == region.readFromMemory(data, sizeof(data)));
+    }
+    {
+        // ends with empty yspan
+        int32_t data[] = {12, 0, 0, 10, 10, 2, 2, 0, 10, 2, 0, 4, 6, 10,
+                          2147483647, 15, 0, 2147483647, 2147483647};
+        REPORTER_ASSERT(r, 0 == region.readFromMemory(data, sizeof(data)));
+    }
+    {
+        // y intervals out of order
+        int32_t data[] = {19, 0, -20, 30, 10, 3, 4, 0, 10, 2, 0, 10, 20, 30,
+                          2147483647, -20, 0, 2147483647, -10, 2, 0, 10, 20, 30,
+                          2147483647, 2147483647};
+        REPORTER_ASSERT(r, 0 == region.readFromMemory(data, sizeof(data)));
+    }
+    {
+        // x intervals out of order
+        int32_t data[] = {9, 0, 0, 10, 10, 1, 2, 0, 10, 2, 6, 10, 0, 4,
+                          2147483647, 2147483647};
+        REPORTER_ASSERT(r, 0 == region.readFromMemory(data, sizeof(data)));
+    }
 }