Improve syncing between dom distiller and the print preview request

chrome/browser/ui/webui/print_preview/print_preview_distiller.cc

Index: chrome/browser/ui/webui/print_preview/print_preview_distiller.cc
diff --git a/chrome/browser/ui/webui/print_preview/print_preview_distiller.cc b/chrome/browser/ui/webui/print_preview/print_preview_distiller.cc
index 213078ceb85605bc3e15201f11a47283ef373f82..40994ef99046f562042d1b95ee5e4782bf27e7e7 100644
--- a/chrome/browser/ui/webui/print_preview/print_preview_distiller.cc
+++ b/chrome/browser/ui/webui/print_preview/print_preview_distiller.cc
@@ -21,6 +21,7 @@
 #include "chrome/common/prerender_messages.h"
 #include "components/dom_distiller/content/browser/distiller_javascript_utils.h"
 #include "components/printing/common/print_messages.h"
+#include "content/public/browser/navigation_details.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_process_host.h"
@@ -135,25 +136,10 @@ class PrintPreviewDistiller::WebContentsDelegateImpl
         render_frame_host->GetRoutingID(), true));
   }
 
-  void DidFinishLoad(content::RenderFrameHost* render_frame_host,
-                     const GURL& validated_url) override {
-    // Ask the page to trigger an anchor navigation once the distilled
-    // contents are added to the page.
-    dom_distiller::RunIsolatedJavaScript(
-        web_contents()->GetMainFrame(),
-        "navigate_on_initial_content_load = true;");
-  }
-
-  void DidNavigateMainFrame(
-      const content::LoadCommittedDetails& details,
-      const content::FrameNavigateParams& params) override {
-    // The second content loads signals that the distilled contents have
-    // been delivered to the page via inline JavaScript execution.
-    if (web_contents()->GetController().GetEntryCount() > 1) {
-      RenderViewHost* rvh = web_contents()->GetRenderViewHost();
-      rvh->Send(new PrintMsg_InitiatePrintPreview(rvh->GetRoutingID(), false));
-      rvh->Send(new PrintMsg_PrintPreview(rvh->GetRoutingID(), *settings_));
-    }
+  void DoPrintPreview() {
+    RenderViewHost* rvh = web_contents()->GetRenderViewHost();
+    rvh->Send(new PrintMsg_InitiatePrintPreview(rvh->GetRoutingID(), false));
+    rvh->Send(new PrintMsg_PrintPreview(rvh->GetRoutingID(), *settings_));
   }
 
   void DidGetRedirectForResourceRequest(
@@ -169,6 +155,18 @@ class PrintPreviewDistiller::WebContentsDelegateImpl
     on_failed_callback_.Run();
   }
 
+  void DidNavigateMainFrame(
+      const content::LoadCommittedDetails& details,
+      const content::FrameNavigateParams& params) override {
+    // Wait until we are done distilling the article and the target
+    // WebContents is ready for printing.
+    // The navigation to notify print preview that content is on the page will
+    // be an in-page navigation.
+    if (!details.is_in_page)
+      return;
+    DoPrintPreview();

[wychen, 2016/04/11 21:37:21]

Add a TODO saying resources are not necessarily ready at this point.

[mvendramini_hp, 2016/04/12 13:01:27]

Done - added both our names. I would need some help addressing it in the next CL
though.

+  }
+
   void Observe(int type,
                const content::NotificationSource& source,
                const content::NotificationDetails& details) override {