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

components/pdf/renderer/pepper_pdf_host.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/pdf/renderer/pepper_pdf_host.h"
 
 #include "components/pdf/common/pdf_messages.h"
 #include "components/pdf/renderer/pdf_accessibility_tree.h"
 #include "content/public/common/referrer.h"
 #include "content/public/renderer/pepper_plugin_instance.h"
@@ skipping 124 matching lines @@
   return PP_OK;
 }
 
 int32_t PepperPDFHost::OnHostMsgHasUnsupportedFeature(
     ppapi::host::HostMessageContext* context) {
   content::PepperPluginInstance* instance =
       host_->GetPluginInstance(pp_instance());
   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;
 }
 
 int32_t PepperPDFHost::OnHostMsgPrint(
     ppapi::host::HostMessageContext* context) {
   return InvokePrintingForInstance(pp_instance()) ? PP_OK : PP_ERROR_FAILED;
 }
 
 int32_t PepperPDFHost::OnHostMsgSaveAs(
     ppapi::host::HostMessageContext* context) {
   content::PepperPluginInstance* instance =
       host_->GetPluginInstance(pp_instance());
   if (!instance)
     return PP_ERROR_FAILED;
+
+  content::RenderView* render_view = instance->GetRenderView();
+  if (!render_view)
+    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.

   content::Referrer referrer;
   referrer.url = url;
   referrer.policy = blink::WebReferrerPolicyDefault;
   referrer = content::Referrer::SanitizeForRequest(url, referrer);
   render_view->Send(
       new PDFHostMsg_PDFSaveURLAs(render_view->GetRoutingID(), url, referrer));
   return PP_OK;
 }
 
 int32_t PepperPDFHost::OnHostMsgSetSelectedText(
@@ skipping 52 matching lines @@
 }
 
 void PepperPDFHost::CreatePdfAccessibilityTreeIfNeeded() {
   if (!pdf_accessibility_tree_) {
     pdf_accessibility_tree_.reset(new PdfAccessibilityTree(
         host_, pp_instance()));
   }
 }
 
 }  // namespace pdf