Allow Mojo structs as map keys

mojo/public/cpp/bindings/tests/wtf_map_unittest.cc

Index: mojo/public/cpp/bindings/tests/wtf_map_unittest.cc
diff --git a/mojo/public/cpp/bindings/tests/wtf_map_unittest.cc b/mojo/public/cpp/bindings/tests/wtf_map_unittest.cc
index a70c134ac254f51a80aca51082ee2fe2b49450a5..d5888249cf6d1ca60e422e3fe4407bbf2f5bc8bb 100644
--- a/mojo/public/cpp/bindings/tests/wtf_map_unittest.cc
+++ b/mojo/public/cpp/bindings/tests/wtf_map_unittest.cc
@@ -8,6 +8,7 @@
 #include "mojo/public/cpp/bindings/tests/container_test_util.h"
 #include "mojo/public/cpp/bindings/tests/map_common_test.h"
 #include "mojo/public/cpp/bindings/wtf_array.h"
+#include "mojo/public/interfaces/bindings/tests/rect.mojom-blink.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/WebKit/Source/wtf/text/WTFString.h"
 
@@ -62,6 +63,30 @@ TEST_F(WTFMapTest, MoveFromAndToWTFHashMap_MoveOnly) {
   ASSERT_TRUE(mojo_map.is_null());
 }
 
+static blink::RectPtr MakeRect(int32_t x,
+                               int32_t y,
+                               int32_t width,
+                               int32_t height) {
+  blink::RectPtr rect_ptr = blink::Rect::New();
+  rect_ptr->x = x;
+  rect_ptr->y = y;
+  rect_ptr->width = width;
+  rect_ptr->height = height;
+  return rect_ptr;
+}
+
+TEST_F(WTFMapTest, StructKey) {
+  WTF::HashMap<blink::RectPtr, int32_t> map;
+  map.add(MakeRect(1, 2, 3, 4), 123);
+
+  blink::RectPtr key = MakeRect(1, 2, 3, 4);
+  ASSERT_NE(map.end(), map.find(key));
+  ASSERT_EQ(123, map.find(key)->value);
+
+  map.remove(key);
+  ASSERT_EQ(0u, map.size());
+}
+
 }  // namespace
 }  // namespace test
 }  // namespace mojo