Plugin Power Saver: Add missing RenderFrame null-checks in placeholders

chrome/renderer/plugins/chrome_plugin_placeholder.cc

 // Copyright 2013 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 "chrome/renderer/plugins/chrome_plugin_placeholder.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/command_line.h"
@@ skipping 217 matching lines @@
     prerender::PrerenderMode mode) {
   OnSetIsPrerendering(mode != prerender::NO_PRERENDER);
 }
 
 void ChromePluginPlaceholder::PluginListChanged() {
   if (!GetFrame() || !plugin())
     return;
 
   ChromeViewHostMsg_GetPluginInfo_Output output;
   std::string mime_type(GetPluginParams().mime_type.Utf8());
   render_frame()->Send(new ChromeViewHostMsg_GetPluginInfo(

[raymes, 2017/04/30 23:34:33]

Do we need to check on this occasion too?

[tommycli, 2017/05/01 15:37:18]

Hi. GetFrame() is an equivalent check. It returns a variable which is also
cleared by RenderFrameObserver::OnDestruct.

If you prefer, I'm happy to add a render_frame() nullcheck too, it's just
strictly speaking unnecessary. Or I can add a comment.

[raymes, 2017/05/01 22:10:26]

Ah that makes sense. Thanks :) Maybe add a comment? 

[tommycli, 2017/05/01 22:15:55]

Done. Thanks. I added a comment and DCHECK on the following line. I'm going to
send this in bypassing CQ, since ChromeOS TPM needs this crash fix in by 4PM,
and we have high confidence in it.

       routing_id(), GURL(GetPluginParams().url),
       GetFrame()->Top()->GetSecurityOrigin(), mime_type, &output));
   if (output.status == status_)
     return;
   blink::WebPlugin* new_plugin = ChromeContentRendererClient::CreatePlugin(
       render_frame(), GetFrame(), GetPluginParams(), output);
   ReplacePlugin(new_plugin);
   if (!new_plugin) {
     PluginUMAReporter::GetInstance()->ReportPluginMissing(
         GetPluginParams().mime_type.Utf8(), GURL(GetPluginParams().url));
@@ skipping 33 matching lines @@
 
 v8::Local<v8::Value> ChromePluginPlaceholder::GetV8Handle(
     v8::Isolate* isolate) {
   return gin::CreateHandle(isolate, this).ToV8();
 }
 
 void ChromePluginPlaceholder::ShowContextMenu(
     const blink::WebMouseEvent& event) {
   if (context_menu_request_id_)
     return;  // Don't allow nested context menu requests.
+  if (!render_frame())
+    return;
 
   content::ContextMenuParams params;
 
   if (!title_.empty()) {
     content::MenuItem name_item;
     name_item.label = title_;
     params.custom_items.push_back(name_item);
 
     content::MenuItem separator_item;
     separator_item.type = content::MenuItem::SEPARATOR;
@@ skipping 52 matching lines @@
     new PluginPreroller(render_frame(), GetFrame(), GetPluginParams(),
                         GetPluginInfo(), GetIdentifier(), title_,
                         l10n_util::GetStringFUTF16(IDS_PLUGIN_BLOCKED, title_),
                         throttler.get());
   }
   return render_frame()->CreatePlugin(GetFrame(), GetPluginInfo(),
                                       GetPluginParams(), std::move(throttler));
 }
 
 void ChromePluginPlaceholder::OnBlockedTinyContent() {
+  DCHECK(render_frame());
   if (did_send_blocked_content_notification_)
     return;
 
   did_send_blocked_content_notification_ = true;
   ContentSettingsObserver::Get(render_frame())
       ->DidBlockContentType(CONTENT_SETTINGS_TYPE_PLUGINS, title_);
 }
 
 gin::ObjectTemplateBuilder ChromePluginPlaceholder::GetObjectTemplateBuilder(
     v8::Isolate* isolate) {
@@ skipping 11 matching lines @@
 
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnablePluginPlaceholderTesting)) {
     builder.SetMethod<void (ChromePluginPlaceholder::*)()>(
         "didFinishIconRepositionForTesting",
         &ChromePluginPlaceholder::DidFinishIconRepositionForTestingCallback);
   }
 
   return builder;
 }