Code:  void TestFlashMessageLoop::DestroyMessageLoopResourceTask(int32_t unused) {
   if (message_loop_) {
     delete message_loop_;
    message_loop_ = NULL;
   } else {
     PP_NOTREACHED();
   }
}

Vulnerability Type: Bypass 
CWE ID: CWE-264
Summary: The PPB_Flash_MessageLoop_Impl::InternalRun function in content/renderer/pepper/ppb_flash_message_loop_impl.cc in the Pepper plugin in Google Chrome before 49.0.2623.75 mishandles nested message loops, which allows remote attackers to bypass the Same Origin Policy via a crafted web site.
Commit Message: Fix PPB_Flash_MessageLoop.

This CL suspends script callbacks and resource loads while running nested message loop using PPB_Flash_MessageLoop.

BUG=569496

Review URL: https://codereview.chromium.org/1559113002

Cr-Commit-Position: refs/heads/master@{#374529}