Added tests to previously broken functionality and added null checks.

sdk/lib/indexed_db/dartium/indexed_db_dartium.dart

Index: sdk/lib/indexed_db/dartium/indexed_db_dartium.dart
diff --git a/sdk/lib/indexed_db/dartium/indexed_db_dartium.dart b/sdk/lib/indexed_db/dartium/indexed_db_dartium.dart
index 71b47ad1c982e43110ecfecc118cef4a3323ff82..0aed114e6f1ab876b03daee7d2e4cf959e3232b8 100644
--- a/sdk/lib/indexed_db/dartium/indexed_db_dartium.dart
+++ b/sdk/lib/indexed_db/dartium/indexed_db_dartium.dart
@@ -471,7 +471,7 @@ class Index extends NativeFieldWrapperClass1 {
     if ((key_OR_range is KeyRange || key_OR_range == null)) {
       return _count_1(key_OR_range);
     }
-    if (?key_OR_range) {
+    if (?key_OR_range && key_OR_range != null) {
       return _count_2(key_OR_range);
     }
     throw new ArgumentError("Incorrect number or type of arguments");
@@ -485,7 +485,7 @@ class Index extends NativeFieldWrapperClass1 {
     if ((key is KeyRange || key == null)) {
       return _get_1(key);
     }
-    if (?key) {
+    if (?key && key != null) {
       return _get_2(key);
     }
     throw new ArgumentError("Incorrect number or type of arguments");
@@ -499,7 +499,7 @@ class Index extends NativeFieldWrapperClass1 {
     if ((key is KeyRange || key == null)) {
       return _getKey_1(key);
     }
-    if (?key) {
+    if (?key && key != null) {
       return _getKey_2(key);
     }
     throw new ArgumentError("Incorrect number or type of arguments");
@@ -513,7 +513,7 @@ class Index extends NativeFieldWrapperClass1 {
     if ((key_OR_range is KeyRange || key_OR_range == null) && (direction is String || direction == null)) {
       return _openCursor_1(key_OR_range, direction);
     }
-    if (?key_OR_range && (direction is String || direction == null)) {
+    if (?key_OR_range && key_OR_range != null && (direction is String || direction == null)) {
       return _openCursor_2(key_OR_range, direction);
     }
     throw new ArgumentError("Incorrect number or type of arguments");
@@ -527,7 +527,7 @@ class Index extends NativeFieldWrapperClass1 {
     if ((key_OR_range is KeyRange || key_OR_range == null) && (direction is String || direction == null)) {
       return _openKeyCursor_1(key_OR_range, direction);
     }
-    if (?key_OR_range && (direction is String || direction == null)) {
+    if (?key_OR_range && key_OR_range != null && (direction is String || direction == null)) {
       return _openKeyCursor_2(key_OR_range, direction);
     }
     throw new ArgumentError("Incorrect number or type of arguments");
@@ -771,7 +771,7 @@ class ObjectStore extends NativeFieldWrapperClass1 {
     if ((key_OR_range is KeyRange || key_OR_range == null)) {
       return _count_1(key_OR_range);
     }
-    if (?key_OR_range) {
+    if (?key_OR_range && key_OR_range != null) {
       return _count_2(key_OR_range);
     }
     throw new ArgumentError("Incorrect number or type of arguments");
@@ -799,7 +799,7 @@ class ObjectStore extends NativeFieldWrapperClass1 {
     if ((key_OR_keyRange is KeyRange || key_OR_keyRange == null)) {
       return _delete_1(key_OR_keyRange);
     }
-    if (?key_OR_keyRange) {
+    if (?key_OR_keyRange && key_OR_keyRange != null) {
       return _delete_2(key_OR_keyRange);
     }
     throw new ArgumentError("Incorrect number or type of arguments");
@@ -817,7 +817,7 @@ class ObjectStore extends NativeFieldWrapperClass1 {
     if ((key is KeyRange || key == null)) {
       return _get_1(key);
     }
-    if (?key) {
+    if (?key && key != null) {
       return _get_2(key);
     }
     throw new ArgumentError("Incorrect number or type of arguments");
@@ -835,7 +835,7 @@ class ObjectStore extends NativeFieldWrapperClass1 {
     if ((key_OR_range is KeyRange || key_OR_range == null) && (direction is String || direction == null)) {
       return _openCursor_1(key_OR_range, direction);
     }
-    if (?key_OR_range && (direction is String || direction == null)) {
+    if (?key_OR_range && key_OR_range != null && (direction is String || direction == null)) {
       return _openCursor_2(key_OR_range, direction);
     }
     throw new ArgumentError("Incorrect number or type of arguments");