Return false in TryNumberToSize if there is a cast error

test/cctest/test-conversions.cc

Index: test/cctest/test-conversions.cc
diff --git a/test/cctest/test-conversions.cc b/test/cctest/test-conversions.cc
index 2fee58a46d11a96f7370c5522fb541c3bce766f0..441bcaa7cd1d759ec667d8fb43677efdfa01f37c 100644
--- a/test/cctest/test-conversions.cc
+++ b/test/cctest/test-conversions.cc
@@ -444,3 +444,19 @@ TEST(NoHandlesForTryNumberToSize) {
     }
   }
 }
+
+TEST(CastErrorInTryNumberToSize) {
+  i::Isolate* isolate = CcTest::i_isolate();
+  UnicodeCache uc;
+  size_t result = 0;
+  {
+    HandleScope scope(isolate);
+    double value = StringToDouble(&uc, "0x10000000000000000",

[ahaas, 2016/12/07 16:20:38]

I think you could just write 
double value = 18446744073709551616.0;
which is 0x10000000000000000. Please add a comment for that, because I think
this is not obvious to see.

[qiuyi.zqy, 2016/12/07 18:13:36]

Done.

+                                  ALLOW_HEX | ALLOW_IMPLICIT_OCTAL);
+    Handle<HeapNumber> heap_number = isolate->factory()->NewHeapNumber(value);
+    bool success = TryNumberToSize(*heap_number, &result);
+    if (success && value > 0) {

[ahaas, 2016/12/07 16:20:38]

I think you could just write "CHECK(!success);" instead of this if-block.

[qiuyi.zqy, 2016/12/07 18:13:36]

Done.

+      CHECK(result != 0);
+    }
+  }
+}