Code:  void PrintWebViewHelper::OnPrintPages() {
   blink::WebLocalFrame* frame;
   if (!GetPrintFrame(&frame))
     return;
  auto plugin = delegate_->GetPdfElement(frame);
  Print(frame, plugin, false);
 }

Vulnerability Type: DoS 
CWE ID: 
Summary: Multiple use-after-free vulnerabilities in the PrintWebViewHelper class in components/printing/renderer/print_web_view_helper.cc in Google Chrome before 45.0.2454.85 allow user-assisted remote attackers to cause a denial of service or possibly have unspecified other impact by triggering nested IPC messages during preparation for printing, as demonstrated by messages associated with PDF documents in conjunction with messages about printer capabilities.
Commit Message: Crash on nested IPC handlers in PrintWebViewHelper

Class is not designed to handle nested IPC. Regular flows also does not
expect them. Still during printing of plugging them may show message
boxes and start nested message loops.
For now we are going just crash. If stats show us that this case is
frequent we will have to do something more complicated.

BUG=502562

Review URL: https://codereview.chromium.org/1228693002

Cr-Commit-Position: refs/heads/master@{#338100}