Fix a crash in pdf::PepperPDFHost::OnHostMsgHasUnsupportedFeature().

components/pdf/renderer/pepper_pdf_host.cc

Index: components/pdf/renderer/pepper_pdf_host.cc
diff --git a/components/pdf/renderer/pepper_pdf_host.cc b/components/pdf/renderer/pepper_pdf_host.cc
index 1355141c2d4d5d9ddd74f6b9b75537f809b2c1cb..609e2406be6c9dc94682149ba90122ac84c2a905 100644
--- a/components/pdf/renderer/pepper_pdf_host.cc
+++ b/components/pdf/renderer/pepper_pdf_host.cc
@@ -142,14 +142,10 @@ int32_t PepperPDFHost::OnHostMsgHasUnsupportedFeature(
   if (!instance)
     return PP_ERROR_FAILED;
 
-  // TODO(thestig): Turn CHECKs into the proper if statement after figuring out
-  // what's wrong for https://crbug.com/627814
-  CHECK(instance->GetContainer());
-  CHECK(instance->GetContainer()->document().frame());

[Lei Zhang, 2016/07/22 20:35:37]

I found this CHECK() failed, but then I looked below and found a better way to
get the render view.

-  CHECK(instance->GetContainer()->document().frame()->view());
-  blink::WebView* view =
-      instance->GetContainer()->document().frame()->view();
-  content::RenderView* render_view = content::RenderView::FromWebView(view);
+  content::RenderView* render_view = instance->GetRenderView();
+  if (!render_view)
+    return PP_ERROR_FAILED;
+
   render_view->Send(
       new PDFHostMsg_PDFHasUnsupportedFeature(render_view->GetRoutingID()));
   return PP_OK;
@@ -166,8 +162,12 @@ int32_t PepperPDFHost::OnHostMsgSaveAs(
       host_->GetPluginInstance(pp_instance());
   if (!instance)
     return PP_ERROR_FAILED;
-  GURL url = instance->GetPluginURL();
+
   content::RenderView* render_view = instance->GetRenderView();

[Lei Zhang, 2016/07/22 20:35:37]

This can also return a nullptr and crash later down, but it's a much rarer
crash.

+  if (!render_view)
+    return PP_ERROR_FAILED;
+
+  GURL url = instance->GetPluginURL();
   content::Referrer referrer;
   referrer.url = url;
   referrer.policy = blink::WebReferrerPolicyDefault;