Add type for testing to interstitials.

content/public/browser/interstitial_page_delegate.cc

Index: content/public/browser/interstitial_page_delegate.cc
diff --git a/content/common/gpu/media/vp8_picture.cc b/content/public/browser/interstitial_page_delegate.cc
similarity index 59%
copy from content/common/gpu/media/vp8_picture.cc
copy to content/public/browser/interstitial_page_delegate.cc
index 764c3b1bd739a88810bbcb1ca47dbafec9c036e0..60a441842b4af1ee688de6c4283e813f016059ec 100644
--- a/content/common/gpu/media/vp8_picture.cc
+++ b/content/public/browser/interstitial_page_delegate.cc
@@ -2,17 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "content/common/gpu/media/vp8_picture.h"
+#include "content/public/browser/interstitial_page_delegate.h"
 
 namespace content {
-
-VP8Picture::VP8Picture() {
-}
-
-VP8Picture::~VP8Picture() {
-}
-
-V4L2VP8Picture* VP8Picture::AsV4L2VP8Picture() {
+InterstitialPageDelegate::TypeID InterstitialPageDelegate::GetTypeForTesting()
+    const {
   return nullptr;
 }