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

base/android/jni_string.cc

 // Copyright (c) 2012 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 "base/android/jni_string.h"
 
 #include "base/android/jni_android.h"
 #include "base/logging.h"
 #include "base/strings/utf_string_conversions.h"
 
 namespace {
 
 // Internal version that does not use a scoped local pointer.
 jstring ConvertUTF16ToJavaStringImpl(JNIEnv* env,
                                      const base::StringPiece16& str) {
   jstring result = env->NewString(str.data(), str.length());
   base::android::CheckException(env);
   return result;
 }
 
 }  // namespace
 
 namespace base {
 namespace android {
 
 void ConvertJavaStringToUTF8(JNIEnv* env, jstring str, std::string* result) {
-  if (!str) {
-    LOG(WARNING) << "ConvertJavaStringToUTF8 called with null string.";
-    result->clear();
-    return;
-  }
+  DCHECK(str);
   const jsize length = env->GetStringLength(str);
   if (!length) {
     result->clear();
     CheckException(env);
     return;
   }
   // JNI's GetStringUTFChars() returns strings in Java "modified" UTF8, so
   // instead get the String in UTF16 and convert using chromium's conversion
   // function that yields plain (non Java-modified) UTF8.
   const jchar* chars = env->GetStringChars(str, NULL);
@@ skipping 25 matching lines @@
   // Further, Dalvik requires the string passed into NewStringUTF() to come from
   // a trusted source. We can't guarantee that all UTF8 will be sanitized before
   // it gets here, so constructing via UTF16 side-steps this issue.
   // (Dalvik stores strings internally as UTF16 anyway, so there shouldn't be
   // a significant performance hit by doing it this way).
   return ScopedJavaLocalRef<jstring>(env, ConvertUTF16ToJavaStringImpl(
       env, UTF8ToUTF16(str)));
 }
 
 void ConvertJavaStringToUTF16(JNIEnv* env, jstring str, string16* result) {
-  if (!str) {
-    LOG(WARNING) << "ConvertJavaStringToUTF16 called with null string.";
-    result->clear();
-    return;
-  }
+  DCHECK(str);
   const jsize length = env->GetStringLength(str);
   if (!length) {
     result->clear();
     CheckException(env);
     return;
   }
   const jchar* chars = env->GetStringChars(str, NULL);
   DCHECK(chars);
   // GetStringChars isn't required to NULL-terminate the strings
   // it returns, so the length must be explicitly checked.
@@ skipping 18 matching lines @@
 
 ScopedJavaLocalRef<jstring> ConvertUTF16ToJavaString(
     JNIEnv* env,
     const base::StringPiece16& str) {
   return ScopedJavaLocalRef<jstring>(env,
                                      ConvertUTF16ToJavaStringImpl(env, str));
 }
 
 }  // namespace android
 }  // namespace base