Require WebLocalFrame to be created with a non-null client

third_party/WebKit/Source/web/ChromeClientImpl.cpp

Index: third_party/WebKit/Source/web/ChromeClientImpl.cpp
diff --git a/third_party/WebKit/Source/web/ChromeClientImpl.cpp b/third_party/WebKit/Source/web/ChromeClientImpl.cpp
index 17c5196c58af0da104f2b2db6c66d934216c04b5..f28521197e3537525b78dc6acf7cb4b530d1fb58 100644
--- a/third_party/WebKit/Source/web/ChromeClientImpl.cpp
+++ b/third_party/WebKit/Source/web/ChromeClientImpl.cpp
@@ -1131,11 +1131,9 @@ 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));
@@ -1145,15 +1143,15 @@ void ChromeClientImpl::installSupplements(LocalFrame& frame)
     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