Convert dom_distiller::WebContentsMainFrameObserver to use the new navigation callbacks.

components/dom_distiller/content/browser/web_contents_main_frame_observer.cc

Index: components/dom_distiller/content/browser/web_contents_main_frame_observer.cc
diff --git a/components/dom_distiller/content/browser/web_contents_main_frame_observer.cc b/components/dom_distiller/content/browser/web_contents_main_frame_observer.cc
index 51fd6906c221b9a860cd5f49b104d06bfaf1729d..d3e48c759e5bf38d6933dafb3c533c7c4ee0121d 100644
--- a/components/dom_distiller/content/browser/web_contents_main_frame_observer.cc
+++ b/components/dom_distiller/content/browser/web_contents_main_frame_observer.cc
@@ -4,7 +4,7 @@
 
 #include "components/dom_distiller/content/browser/web_contents_main_frame_observer.h"
 
-#include "content/public/browser/navigation_details.h"
+#include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_observer.h"
@@ -31,13 +31,16 @@ void WebContentsMainFrameObserver::DocumentLoadedInFrame(
   }
 }
 
-void WebContentsMainFrameObserver::DidNavigateMainFrame(
-    const content::LoadCommittedDetails& details,
-    const content::FrameNavigateParams& params) {
-  if (details.is_navigation_to_different_page()) {
-    is_document_loaded_in_main_frame_ = false;
-    is_initialized_ = true;
+void WebContentsMainFrameObserver::DidFinishNavigation(
+    content::NavigationHandle* navigation_handle) {
+  if (!navigation_handle->IsInMainFrame() ||
+      !navigation_handle->HasCommitted() ||
+      navigation_handle->IsSamePage()) {
+    return;
   }
+
+  is_document_loaded_in_main_frame_ = false;
+  is_initialized_ = true;
 }
 
 void WebContentsMainFrameObserver::RenderProcessGone(