Add Dart_IdentityHash to the embedding API.

runtime/vm/dart_api_impl_test.cc

Index: runtime/vm/dart_api_impl_test.cc
diff --git a/runtime/vm/dart_api_impl_test.cc b/runtime/vm/dart_api_impl_test.cc
index 1ba3b9cefcfcb9d206c00f948f79ac627d0435dc..41f893bb96bfcaa7ac8ed9e510f7817bf531b36f 100644
--- a/runtime/vm/dart_api_impl_test.cc
+++ b/runtime/vm/dart_api_impl_test.cc
@@ -521,20 +521,32 @@ TEST_CASE(Null) {
 
 
 TEST_CASE(IdentityEquals) {
-  Dart_Handle five = NewString("5");
-  Dart_Handle five_again = NewString("5");
-  Dart_Handle seven = NewString("7");
+  Dart_Handle five = Dart_NewInteger(5);
+  Dart_Handle five_again = Dart_NewInteger(5);
+  Dart_Handle mint = Dart_NewInteger(0xFFFFFFFF);
+  Dart_Handle mint_again = Dart_NewInteger(0xFFFFFFFF);
+  Dart_Handle abc = NewString("abc");
+  Dart_Handle abc_again = NewString("abc");
+  Dart_Handle xyz = NewString("abc");
   Dart_Handle dart_core = NewString("dart:core");
   Dart_Handle dart_mirrors = NewString("dart:mirrors");
 
   // Same objects.
   EXPECT(Dart_IdentityEquals(five, five));
+  EXPECT(Dart_IdentityEquals(mint, mint));
+  EXPECT(Dart_IdentityEquals(abc, abc));
+  EXPECT(Dart_IdentityEquals(xyz, xyz));
 
-  // Equal objects.
-  EXPECT(!Dart_IdentityEquals(five, five_again));
+  // Equal objects with special spec rules.
+  EXPECT(Dart_IdentityEquals(five, five_again));
+  EXPECT(Dart_IdentityEquals(mint, mint_again));
+
+  // Equal objects without special spec rules.
+  EXPECT(!Dart_IdentityEquals(abc, abc_again));
 
   // Different objects.
-  EXPECT(!Dart_IdentityEquals(five, seven));
+  EXPECT(!Dart_IdentityEquals(five, mint));
+  EXPECT(!Dart_IdentityEquals(abc, xyz));
 
   // Case where identical() is not the same as pointer equality.
   Dart_Handle nan1 = Dart_NewDouble(NAN);
@@ -559,6 +571,47 @@ TEST_CASE(IdentityEquals) {
 }
 
 
+TEST_CASE(IdentityHash) {
+  Dart_Handle five = Dart_NewInteger(5);
+  Dart_Handle five_again = Dart_NewInteger(5);
+  Dart_Handle mint = Dart_NewInteger(0xFFFFFFFF);
+  Dart_Handle mint_again = Dart_NewInteger(0xFFFFFFFF);
+  Dart_Handle abc = NewString("abc");
+  // Dart_Handle abc_again = NewString("abc");
+  Dart_Handle xyz = NewString("abc");
+  Dart_Handle dart_core = NewString("dart:core");
+  Dart_Handle dart_mirrors = NewString("dart:mirrors");
+
+  // Same objects.
+  EXPECT_EQ(Dart_IdentityHash(five), Dart_IdentityHash(five));
+  EXPECT_EQ(Dart_IdentityHash(mint), Dart_IdentityHash(mint));
+  EXPECT_EQ(Dart_IdentityHash(abc), Dart_IdentityHash(abc));
+  EXPECT_EQ(Dart_IdentityHash(xyz), Dart_IdentityHash(xyz));
+
+  // Equal objects with special spec rules.
+  EXPECT_EQ(Dart_IdentityHash(five), Dart_IdentityHash(five_again));
+  EXPECT_EQ(Dart_IdentityHash(mint), Dart_IdentityHash(mint_again));
+
+  // Note abc and abc_again are not required to have equal identity hashes.
+
+  // Case where identical() is not the same as pointer equality.
+  Dart_Handle nan1 = Dart_NewDouble(NAN);
+  Dart_Handle nan2 = Dart_NewDouble(NAN);
+  EXPECT_EQ(Dart_IdentityHash(nan1), Dart_IdentityHash(nan2));
+
+  // Non-instance objects.
+  {
+    Isolate* isolate = Isolate::Current();
+    DARTSCOPE(isolate);
+    Dart_Handle lib1 = Dart_LookupLibrary(dart_core);
+    Dart_Handle lib2 = Dart_LookupLibrary(dart_mirrors);
+
+    EXPECT_EQ(Dart_IdentityHash(lib1), Dart_IdentityHash(lib1));
+    EXPECT_EQ(Dart_IdentityHash(lib2), Dart_IdentityHash(lib2));
+  }
+}
+
+
 TEST_CASE(ObjectEquals) {
   bool equal = false;
   Dart_Handle five = NewString("5");