[ios] GridCommands implementation in TabGridMediator

Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I32c9bf8ba1a131268a71d2a2bcb04ef7b49b7665
Reviewed-on: https://chromium-review.googlesource.com/943934
Commit-Queue: edchin <edchin@chromium.org>
Reviewed-by: edchin <edchin@chromium.org>
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#540381}

ios/chrome/browser/ui/tab_grid/tab_grid_mediator.mm

@@ -163,15 +163,15 @@ NSArray* CreateItems(WebStateList* webStateList) {
 }
 
 - (void)selectItemAtIndex:(NSUInteger)index {
-  // TODO(crbug.com/804503) : Add alerts for unimplemented controls.
+  self.webStateList->ActivateWebStateAt(index);
 }
 
 - (void)closeItemAtIndex:(NSUInteger)index {
-  // TODO(crbug.com/804503) : Add alerts for unimplemented controls.
+  self.webStateList->CloseWebStateAt(index, WebStateList::CLOSE_USER_ACTION);
 }
 
 - (void)closeAllItems {
-  // TODO(crbug.com/804503) : Add alerts for unimplemented controls.
+  self.webStateList->CloseAllWebStates(WebStateList::CLOSE_USER_ACTION);
 }
 
 #pragma mark - GridImageDataSource

ios/chrome/browser/ui/tab_grid/tab_grid_mediator_unittest.mm

@@ -9,6 +9,7 @@
 
 #include "base/test/scoped_task_environment.h"
 #import "ios/chrome/browser/tabs/tab_model.h"
+#import "ios/chrome/browser/ui/tab_grid/grid_commands.h"
 #import "ios/chrome/browser/ui/tab_grid/grid_consumer.h"
 #import "ios/chrome/browser/ui/tab_grid/grid_item.h"
 #import "ios/chrome/browser/web/tab_id_tab_helper.h"
@@ -122,3 +123,25 @@ TEST_F(TabGridMediatorTest, ConsumerMoveItem) {
   web_state_list_->MoveWebStateAt(1, 2);
   [[consumer_ verify] moveItemFromIndex:1 toIndex:2 selectedIndex:2];
 }
+
+// Tests that the active index is updated when |-selectItemAtIndex:| is called.
+TEST_F(TabGridMediatorTest, SelectItemCommand) {
+  // Previous selected index is 1.
+  [mediator_ selectItemAtIndex:2];
+  EXPECT_EQ(2, web_state_list_->active_index());
+}
+
+// Tests that the webStateList count is decremented when |-closeItemAtIndex:| is
+// called.
+TEST_F(TabGridMediatorTest, CloseItemCommand) {
+  // Previously there were 3 items.
+  [mediator_ closeItemAtIndex:1];
+  EXPECT_EQ(2, web_state_list_->count());
+}
+
+// Tests that the webStateList is empty when |-closeAllItems| is called.
+TEST_F(TabGridMediatorTest, CloseAllItemsCommand) {
+  // Previously there were 3 items.
+  [mediator_ closeAllItems];
+  EXPECT_EQ(0, web_state_list_->count());
+}