Cleanups for http://codereview.chromium.org/3176027

chrome/browser/renderer_host/render_widget_host_view_mac.mm

Index: chrome/browser/renderer_host/render_widget_host_view_mac.mm
diff --git a/chrome/browser/renderer_host/render_widget_host_view_mac.mm b/chrome/browser/renderer_host/render_widget_host_view_mac.mm
index 87b0fdca6e61347cc4d049d3256e6f1b1bbd6bb5..04fc6e0047add4f7e565b9e7f5c58ab1689949f7 100644
--- a/chrome/browser/renderer_host/render_widget_host_view_mac.mm
+++ b/chrome/browser/renderer_host/render_widget_host_view_mac.mm
@@ -137,7 +137,7 @@ void DisablePasswordInput() {
 
 // Informal protocol implemented by windows that need to be informed explicitly
 // about underlay surfaces.
-@protocol UnderlayableSurface
+@interface RenderWidgetHostViewCocoa (UnderlayableSurface)
 - (void)underlaySurfaceAdded;
 - (void)underlaySurfaceRemoved;
 @end
@@ -319,13 +319,11 @@ static CVReturn DrawOneAcceleratedPluginCallback(
     return;
   }
 
-  if ([self window] &&
-      [[self window] respondsToSelector:@selector(underlaySurfaceRemoved)]) {
+  if ([[self window] respondsToSelector:@selector(underlaySurfaceRemoved)]) {
     [static_cast<id>([self window]) underlaySurfaceRemoved];
   }
 
-  if (newWindow &&
-      [newWindow respondsToSelector:@selector(underlaySurfaceAdded)]) {
+  if ([newWindow respondsToSelector:@selector(underlaySurfaceAdded)]) {
     [static_cast<id>(newWindow) underlaySurfaceAdded];
   }
 }