Switch the inheritance of WebViewClient from WebWidgetClient to protected.

third_party/WebKit/Source/web/tests/FrameSerializerTest.cpp

Index: third_party/WebKit/Source/web/tests/FrameSerializerTest.cpp
diff --git a/third_party/WebKit/Source/web/tests/FrameSerializerTest.cpp b/third_party/WebKit/Source/web/tests/FrameSerializerTest.cpp
index d3aa43a526a6cba8dbfbc187e155051304cc04ab..8e7e207923f0a7eb5de34e0429f3437c32a5b55a 100644
--- a/third_party/WebKit/Source/web/tests/FrameSerializerTest.cpp
+++ b/third_party/WebKit/Source/web/tests/FrameSerializerTest.cpp
@@ -69,7 +69,7 @@ protected:
     void SetUp() override
     {
         // We want the images to load and JavaScript to be on.
-        m_helper.initialize(true, 0, 0, &configureSettings);
+        m_helper.initialize(true, nullptr, nullptr, nullptr, &configureSettings);
     }
 
     void TearDown() override