[Android] Further speculative fixes for search engine crashes.

chrome/browser/search_engines/template_url_service_android.cc

 // Copyright (c) 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/search_engines/template_url_service_android.h"
 
 #include <stddef.h>
 
 #include "base/android/jni_string.h"
 #include "base/bind.h"
@@ skipping 283 matching lines @@
 
 base::android::ScopedJavaLocalRef<jstring>
 TemplateUrlServiceAndroid::GetSearchEngineUrlFromTemplateUrl(
     JNIEnv* env,
     const JavaParamRef<jobject>& obj,
     const JavaParamRef<jstring>& jkeyword) {
   base::string16 keyword =
       base::android::ConvertJavaStringToUTF16(env, jkeyword);
   TemplateURL* template_url =
       template_url_service_->GetTemplateURLForKeyword(keyword);
-  CHECK(template_url) << "Failed to find template URL for keyword: " << keyword;
+  if (!template_url)
+    return base::android::ScopedJavaLocalRef<jstring>(env, nullptr);
   std::string url(template_url->url_ref().ReplaceSearchTerms(
       TemplateURLRef::SearchTermsArgs(base::ASCIIToUTF16("query")),
       template_url_service_->search_terms_data()));
   return base::android::ConvertUTF8ToJavaString(env, url);
 }
 
 base::android::ScopedJavaLocalRef<jstring>
 TemplateUrlServiceAndroid::AddSearchEngineForTesting(
     JNIEnv* env,
     const base::android::JavaParamRef<jobject>& obj,
@@ skipping 35 matching lines @@
 static jlong Init(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   TemplateUrlServiceAndroid* template_url_service_android =
       new TemplateUrlServiceAndroid(env, obj);
   return reinterpret_cast<intptr_t>(template_url_service_android);
 }
 
 // static
 bool TemplateUrlServiceAndroid::Register(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }