Fix a typo: LINUX -> OS_LINUX

Fix a typo in the previous CL (http://src.chromium.org/viewvc/chrome?view=rev&revision=148520).

TBR=jam@chromium.org
BUG=118571
TEST=None

Review URL: https://chromiumcodereview.appspot.com/10821044

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@148602 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/renderer_host/render_widget_host_impl.cc

@@ -503,7 +503,7 @@ void RenderWidgetHostImpl::CopyFromBackingStore(
   if (view_ && is_accelerated_compositing_active_) {
     TRACE_EVENT0("browser",
         "RenderWidgetHostImpl::CopyFromBackingStore::FromCompositingSurface");
-#if defined(USE_AURA) || defined(LINUX)
+#if defined(USE_AURA) || defined(OS_LINUX)
     gfx::Rect copy_rect = src_subrect.IsEmpty() ?
         gfx::Rect(view_->GetViewBounds().size()) : src_subrect;
 #else