Remove implicit conversions from scoped_refptr to T* in c/b/renderer_host/pepper

This patch was generated by running the rewrite_scoped_refptr clang tool
on a ChromeOS build.

BUG=110610

Review URL: https://codereview.chromium.org/574463003

Cr-Commit-Position: refs/heads/master@{#294889}

chrome/browser/renderer_host/pepper/pepper_platform_verification_message_filter.cc

@@ -71,7 +71,7 @@ int32_t PepperPlatformVerificationMessageFilter::OnChallengePlatform(
     return PP_OK_COMPLETIONPENDING;
   }
 
-  if (!pv_)
+  if (!pv_.get())
     pv_ = new PlatformVerificationFlow();
 
   pv_->ChallengePlatformKey(