Pass the size to the RenderView on creation.

content/public/test/render_view_test.h

Index: content/public/test/render_view_test.h
diff --git a/content/public/test/render_view_test.h b/content/public/test/render_view_test.h
index baab05aa9ca26026b57f95962c775bc0b5f0ad85..46dc35ce15f9f911abd67b875a99af45e3a673b6 100644
--- a/content/public/test/render_view_test.h
+++ b/content/public/test/render_view_test.h
@@ -19,6 +19,8 @@
 #include "third_party/WebKit/public/platform/Platform.h"
 #include "third_party/WebKit/public/web/WebFrame.h"
 
+struct ViewMsg_Resize_Params;
+
 namespace blink {
 class WebWidget;
 }
@@ -133,6 +135,9 @@ class RenderViewTest : public testing::Test {
   virtual ContentBrowserClient* CreateContentBrowserClient();
   virtual ContentRendererClient* CreateContentRendererClient();
 
+  // Allows a subclass to customize the initial size of the RenderView.
+  virtual scoped_ptr<ViewMsg_Resize_Params> InitialSizeParams();
+
   // testing::Test
   void SetUp() override;