Switch the inheritance of WebViewClient from WebWidgetClient to protected.

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 8760f9cd761d4e48f23ccc93e167ebbd93251d49..60767e262a74ca723843e41659448c4a34f9bb61 100644
--- a/third_party/WebKit/Source/web/ChromeClientImpl.cpp
+++ b/third_party/WebKit/Source/web/ChromeClientImpl.cpp
@@ -565,13 +565,8 @@ IntRect ChromeClientImpl::viewportToScreen(const IntRect& rectInViewport, const
     DCHECK(widget->isFrameView());
     const FrameView* view = toFrameView(widget);
     LocalFrame* frame = view->frame().localFrameRoot();
-    WebWidgetClient* client = nullptr;
 
-    // TODO(kenrb): Consolidate this to a single case when WebViewFrameWidget refactor is complete.
-    if (WebLocalFrameImpl::fromFrame(frame) && WebLocalFrameImpl::fromFrame(frame)->frameWidget() && WebLocalFrameImpl::fromFrame(frame)->frameWidget()->forSubframe())
-        client = toWebFrameWidgetImpl(WebLocalFrameImpl::fromFrame(frame)->frameWidget())->client();
-    else
-        client = m_webView->client();
+    WebWidgetClient* client = WebLocalFrameImpl::fromFrame(frame)->frameWidget()->client();
 
     if (client) {

[dcheng, 2016/04/28 17:30:21]

Out of curiosity, does anyone actually pass a null client?

[lfg, 2016/04/28 17:43:57]

I haven't checked, but this should never happen, since the localRoot should
always have a widget. I'll try to remove the null check and send a separate CL
for that.

         client->convertViewportToWindow(&screenRect);
@@ -579,6 +574,7 @@ IntRect ChromeClientImpl::viewportToScreen(const IntRect& rectInViewport, const
         screenRect.x += windowRect.x;
         screenRect.y += windowRect.y;
     }
+
     return screenRect;
 }