Fix crash when a frame is detached while a PepperPluginInstance is being

content/renderer/pepper/pepper_plugin_instance_impl.cc

Index: content/renderer/pepper/pepper_plugin_instance_impl.cc
diff --git a/content/renderer/pepper/pepper_plugin_instance_impl.cc b/content/renderer/pepper/pepper_plugin_instance_impl.cc
index 1e5d7bbd9922a4ffa34971ea9fafaceb69f7b9d4..6c56fc6a427985460a65f5b3ac57c119e241adf9 100644
--- a/content/renderer/pepper/pepper_plugin_instance_impl.cc
+++ b/content/renderer/pepper/pepper_plugin_instance_impl.cc
@@ -540,8 +540,8 @@ PepperPluginInstanceImpl::PepperPluginInstanceImpl(
   memset(&current_print_settings_, 0, sizeof(current_print_settings_));
   module_->InstanceCreated(this);
 
-  if (render_frame) {  // NULL in tests
-    render_frame->PepperInstanceCreated(this);
+  if (render_frame_) {  // NULL in tests or if the frame has been destroyed.
+    render_frame_->PepperInstanceCreated(this);

[bbudge, 2016/09/07 18:25:07]

I don't see how render_frame_ would be different from render_frame at this point
(before calling RenderFrameImpl::PepperInstanceCreated.) So how is this
different from before?

     view_data_.is_page_visible = !render_frame_->GetRenderWidget()->is_hidden();
 
     // Set the initial focus.
@@ -2144,7 +2144,9 @@ void PepperPluginInstanceImpl::AccessibilityModeChanged() {
     plugin_pdf_interface_->EnableAccessibility(pp_instance());
 }
 
-void PepperPluginInstanceImpl::OnDestruct() { render_frame_ = NULL; }
+void PepperPluginInstanceImpl::OnDestruct() {
+  render_frame_ = nullptr;
+}
 
 void PepperPluginInstanceImpl::OnThrottleStateChange() {
   SendDidChangeView();