Factor DRP PreviewsState logic out of content

chrome/renderer/chrome_content_renderer_client.cc

Index: chrome/renderer/chrome_content_renderer_client.cc
diff --git a/chrome/renderer/chrome_content_renderer_client.cc b/chrome/renderer/chrome_content_renderer_client.cc
index fa44f43c2856ea1a3dafe15368be605bfb5da430..2c53d5b76a08999594bd4afca9bcac6061964e74 100644
--- a/chrome/renderer/chrome_content_renderer_client.cc
+++ b/chrome/renderer/chrome_content_renderer_client.cc
@@ -68,6 +68,7 @@
 #include "components/autofill/content/renderer/password_generation_agent.h"
 #include "components/content_settings/core/common/content_settings_pattern.h"
 #include "components/contextual_search/renderer/overlay_js_render_frame_observer.h"
+#include "components/data_reduction_proxy/content/renderer/content_previews_render_frame_observer.h"
 #include "components/data_reduction_proxy/core/common/data_reduction_proxy_headers.h"
 #include "components/dom_distiller/content/renderer/distillability_agent.h"
 #include "components/dom_distiller/content/renderer/distiller_js_render_frame_observer.h"
@@ -592,6 +593,9 @@ void ChromeContentRendererClient::RenderFrameCreated(
   new SpellCheckPanel(render_frame);
 #endif  // BUILDFLAG(HAS_SPELLCHECK_PANEL)
 #endif
+
+  if (render_frame->IsMainFrame())
+    new data_reduction_proxy::ContentPreviewsRenderFrameObserver(render_frame);
 }
 
 void ChromeContentRendererClient::RenderViewCreated(