DCHECK that jstring to C++ string conversions don't pass in null.

chrome/browser/prerender/external_prerender_handler_android.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/browser/prerender/external_prerender_handler_android.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
 #include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 14 matching lines @@
 namespace {
 
 static bool CheckAndConvertParams(
     JNIEnv* env,
     const JavaParamRef<jobject>& jprofile,
     const JavaParamRef<jstring>& jurl,
     const JavaParamRef<jobject>& jweb_contents,
     GURL* url,
     prerender::PrerenderManager** prerender_manager,
     content::WebContents** web_contents) {
-  if (jurl == NULL)
+  if (!jurl)
     return false;
+
   *url = GURL(ConvertJavaStringToUTF16(env, jurl));
   if (!url->is_valid())
     return false;
 
   Profile* profile = ProfileAndroid::FromProfileAndroid(jprofile);
   *prerender_manager =
       prerender::PrerenderManagerFactory::GetForProfile(profile);
   if (!*prerender_manager)
     return false;
+
   *web_contents = content::WebContents::FromJavaWebContents(jweb_contents);
   return true;
 }
 
 }  // namespace
 
 bool ExternalPrerenderHandlerAndroid::AddPrerender(
     JNIEnv* env,
     const JavaParamRef<jobject>& obj,
     const JavaParamRef<jobject>& jprofile,
     const JavaParamRef<jobject>& jweb_contents,
     const JavaParamRef<jstring>& jurl,
     const JavaParamRef<jstring>& jreferrer,
     jint width,
     jint height,
     jboolean prerender_on_cellular) {
   Profile* profile = ProfileAndroid::FromProfileAndroid(jprofile);
 
   GURL url = GURL(ConvertJavaStringToUTF16(env, jurl));
   if (!url.is_valid())
     return false;
 
-  GURL referrer_url = GURL(ConvertJavaStringToUTF16(env, jreferrer));
-  content::Referrer referrer = referrer_url.is_valid() ?
-      content::Referrer(referrer_url, blink::WebReferrerPolicyDefault) :
-      content::Referrer();
+  content::Referrer referrer;
+  if (!jreferrer.is_null()) {

[mmenke, 2016/03/30 14:52:57]

None of these changes seem to fall under the rubric "DCHECK that jstring to C++
string conversions don't pass in null".  Should update the CL description.

[Bernhard Bauer, 2016/03/30 15:52:09]

Done.

+    GURL referrer_url(ConvertJavaStringToUTF16(env, jreferrer));
+    if (referrer_url.is_valid())
+      referrer =
+          content::Referrer(referrer_url, blink::WebReferrerPolicyDefault);
+  }
+
   PrerenderManager* prerender_manager =
       prerender::PrerenderManagerFactory::GetForProfile(profile);
   if (!prerender_manager)
     return false;
+
   content::WebContents* web_contents =
       content::WebContents::FromJavaWebContents(jweb_contents);
-  if (prerender_handle_.get()) {
+  if (prerender_handle_)
     prerender_handle_->OnNavigateAway();
-  }
+
   if (prerender_on_cellular && net::NetworkChangeNotifier::IsConnectionCellular(
                    net::NetworkChangeNotifier::GetConnectionType())) {
     prerender_handle_.reset(
         prerender_manager->AddPrerenderOnCellularFromExternalRequest(
             url,
             referrer,
             web_contents->GetController().GetDefaultSessionStorageNamespace(),
             gfx::Size(width, height)));
   } else {
     prerender_handle_.reset(
         prerender_manager->AddPrerenderFromExternalRequest(
             url,
             referrer,
             web_contents->GetController().GetDefaultSessionStorageNamespace(),
             gfx::Size(width, height)));
   }
 
-  if (!prerender_handle_)
-    return false;
-  return true;
+  return !!prerender_handle_;
 }
 
 void ExternalPrerenderHandlerAndroid::CancelCurrentPrerender(
     JNIEnv* env,
     const JavaParamRef<jobject>& object) {
   if (!prerender_handle_)
     return;
+
   prerender_handle_->OnCancel();
   prerender_handle_.reset();
 }
 
 static jboolean HasPrerenderedUrl(JNIEnv* env,
                                   const JavaParamRef<jclass>& clazz,
                                   const JavaParamRef<jobject>& jprofile,
                                   const JavaParamRef<jstring>& jurl,
                                   const JavaParamRef<jobject>& jweb_contents) {
   GURL url;
   prerender::PrerenderManager* prerender_manager;
   content::WebContents* web_contents;
   if (!CheckAndConvertParams(env, jprofile, jurl, jweb_contents, &url,
                              &prerender_manager, &web_contents))
     return false;
+
   return prerender_manager->HasPrerenderedUrl(url, web_contents);
 }
 
 static jboolean HasPrerenderedAndFinishedLoadingUrl(
     JNIEnv* env,
     const JavaParamRef<jclass>& clazz,
     const JavaParamRef<jobject>& jprofile,
     const JavaParamRef<jstring>& jurl,
     const JavaParamRef<jobject>& jweb_contents) {
   GURL url;
   prerender::PrerenderManager* prerender_manager;
   content::WebContents* web_contents;
   if (!CheckAndConvertParams(env, jprofile, jurl, jweb_contents, &url,
                              &prerender_manager, &web_contents))
     return false;
+
   return prerender_manager->HasPrerenderedAndFinishedLoadingUrl(url,
                                                                 web_contents);
 }
 
 ExternalPrerenderHandlerAndroid::ExternalPrerenderHandlerAndroid() {}
 
 ExternalPrerenderHandlerAndroid::~ExternalPrerenderHandlerAndroid() {}
 
 static jlong Init(JNIEnv* env, const JavaParamRef<jclass>& clazz) {
   ExternalPrerenderHandlerAndroid* external_handler =
       new ExternalPrerenderHandlerAndroid();
   return reinterpret_cast<intptr_t>(external_handler);
 }
 
 bool ExternalPrerenderHandlerAndroid::RegisterExternalPrerenderHandlerAndroid(
     JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 } // namespace prerender