<webview>: Partially migrate loadcommit event from content to chrome

chrome/browser/webview/webview_constants.cc

Index: chrome/browser/webview/webview_constants.cc
diff --git a/chrome/browser/webview/webview_constants.cc b/chrome/browser/webview/webview_constants.cc
index 5a5e13b298383a019382b348f3691b18bacd91e5..0766a216b8b436985510679840cf446defdc0442 100644
--- a/chrome/browser/webview/webview_constants.cc
+++ b/chrome/browser/webview/webview_constants.cc
@@ -4,9 +4,16 @@
 
 #include "chrome/browser/webview/webview_constants.h"
 
-namespace webview_constants {
+namespace webview {
+
+// Events.
+const char kEventLoadCommit[] = "webview.onLoadCommit";
+
+// Parameters/properties on events.
+const char kIsTopLevel[] = "isTopLevel";
+const char kUrl[] = "url";
 
 // Attributes.
 const char kAttributeApi[] = "api";
 
-}  // namespace webview_constants
+}  // namespace webview