Require WebLocalFrame to be created with a non-null client

third_party/WebKit/Source/web/ChromeClientImpl.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 1112 matching lines @@
 }
 
 double ChromeClientImpl::lastFrameTimeMonotonic() const
 {
     return m_webView->lastFrameTimeMonotonic();
 }
 
 void ChromeClientImpl::installSupplements(LocalFrame& frame)
 {
     WebLocalFrameImpl* webFrame = WebLocalFrameImpl::fromFrame(&frame);
     WebFrameClient* client = webFrame->client();

[esprehn, 2016/09/29 04:28:42]

we should make client() return a reference

[dcheng, 2016/09/29 04:42:38]

Unfortunately, that's not easy, because it can legitimately be null when the
frame is detached.

-    if (client) {
-        providePushControllerTo(frame, client->pushClient());
-        provideUserMediaTo(frame, UserMediaClientImpl::create(client->userMediaClient()));
-    }
-
+    DCHECK(client);

[dcheng, 2016/09/29 04:13:27]

The main goal of this patch is to remove these strange null checks: at this
point, the frame should never be detached (since we're in the middle of
initializing it).

+    providePushControllerTo(frame, client->pushClient());
+    provideUserMediaTo(frame, UserMediaClientImpl::create(client->userMediaClient()));
     provideIndexedDBClientTo(frame, IndexedDBClientImpl::create());
     provideLocalFileSystemTo(frame, LocalFileSystemClient::create());
     provideNavigatorContentUtilsTo(frame, NavigatorContentUtilsClientImpl::create(webFrame));
 
     bool enableWebBluetooth = RuntimeEnabledFeatures::webBluetoothEnabled();
 #if OS(CHROMEOS) || OS(ANDROID) || OS(MACOSX)
     enableWebBluetooth = true;
 #endif
     if (enableWebBluetooth)
-        BluetoothSupplement::provideTo(frame, client ? client->bluetooth() : nullptr);
+        BluetoothSupplement::provideTo(frame, client->bluetooth());
 
-    ScreenOrientationController::provideTo(frame, client ? client->webScreenOrientationClient() : nullptr);
+    ScreenOrientationController::provideTo(frame, client->webScreenOrientationClient());
     if (RuntimeEnabledFeatures::presentationEnabled())
-        PresentationController::provideTo(frame, client ? client->presentationClient() : nullptr);
+        PresentationController::provideTo(frame, client->presentationClient());
     if (RuntimeEnabledFeatures::audioOutputDevicesEnabled())
         provideAudioOutputDeviceClientTo(frame, AudioOutputDeviceClientImpl::create());
     if (RuntimeEnabledFeatures::installedAppEnabled())
-        InstalledAppController::provideTo(frame, client ? client->installedAppClient() : nullptr);
+        InstalledAppController::provideTo(frame, client->installedAppClient());
 }
 
 } // namespace blink