Replace ASSERT with DCHECK in core/

third_party/WebKit/Source/core/page/ContextMenuController.cpp

Index: third_party/WebKit/Source/core/page/ContextMenuController.cpp
diff --git a/third_party/WebKit/Source/core/page/ContextMenuController.cpp b/third_party/WebKit/Source/core/page/ContextMenuController.cpp
index 3193372411282a5ebbacf497efdc2018cb7e4adf..e48f194365d82d8a967cfd1846366efe66694b4a 100644
--- a/third_party/WebKit/Source/core/page/ContextMenuController.cpp
+++ b/third_party/WebKit/Source/core/page/ContextMenuController.cpp
@@ -133,7 +133,7 @@ void ContextMenuController::ShowContextMenuAtPoint(
 
 std::unique_ptr<ContextMenu> ContextMenuController::CreateContextMenu(
     Event* event) {
-  ASSERT(event);
+  DCHECK(event);
 
   if (!event->IsMouseEvent())
     return nullptr;
@@ -181,7 +181,7 @@ void ContextMenuController::ContextMenuItemSelected(
       item->Action() > kContextMenuItemLastCustomTag)
     return;
 
-  ASSERT(menu_provider_);
+  DCHECK(menu_provider_);
   menu_provider_->ContextMenuItemSelected(item);
 }