Remove a circular dependency between render_widget.cc and WebInputEvent.h

https://src.chromium.org/viewvc/chrome?view=rev&revision=175386 added
a utility function to print out event names. This has a circular dependency
on WebInputEvent.h. Make the dependency one way to facilitate adding new
event types.

BUG=160715

Review URL: https://chromiumcodereview.appspot.com/11819037

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@176356 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index f97d0fc..5ff3225 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -108,11 +108,14 @@
     CASE_TYPE(TouchMove);
     CASE_TYPE(TouchEnd);
     CASE_TYPE(TouchCancel);
-    // Don't include default, so that we get an error when new type is added.
+    default:
+      // Must include default to let WebKit::WebInputEvent add new event types
+      // before they're added here.
+      DLOG(WARNING) << "Unhandled WebInputEvent type in GetEventName.\n";
+      break;
   }
 #undef CASE_TYPE
-  NOTREACHED();
-  return "Undefined";
+  return "";
 }
 }
 namespace content {