[Android] Use Blink UTF8<->UTF16 strings conversion in Gin Java Bridge

content/browser/android/java/gin_java_method_invocation_helper.cc

Index: content/browser/android/java/gin_java_method_invocation_helper.cc
diff --git a/content/browser/android/java/gin_java_method_invocation_helper.cc b/content/browser/android/java/gin_java_method_invocation_helper.cc
index ae7d643af5607d7b2da8adf8a8a07041d36ec3ed..254296f74c618de523e65fd9a44fcec18bc28798 100644
--- a/content/browser/android/java/gin_java_method_invocation_helper.cc
+++ b/content/browser/android/java/gin_java_method_invocation_helper.cc
@@ -8,13 +8,13 @@
 
 #include "base/android/event_log.h"
 #include "base/android/jni_android.h"
-#include "base/android/jni_string.h"
 #include "base/float_util.h"
 #include "content/browser/android/java/gin_java_script_to_java_types_coercion.h"
 #include "content/browser/android/java/java_method.h"
 #include "content/browser/android/java/jni_helper.h"
 #include "content/common/android/gin_java_bridge_value.h"
 #include "content/public/browser/browser_thread.h"
+#include "third_party/WebKit/public/platform/WebString.h"
 
 using base::android::AttachCurrentThread;
 using base::android::ScopedJavaLocalRef;
@@ -26,6 +26,15 @@ namespace {
 // See frameworks/base/core/java/android/webkit/EventLogTags.logtags
 const int kObjectGetClassInvocationAttemptLogTag = 70151;
 
+// This is an intermediate solution until we fix http://crbug.com/391492.
+std::string ConvertJavaStringToUTF8(JNIEnv* env, jstring str) {
+  const jchar* chars = env->GetStringChars(str, NULL);
+  DCHECK(chars);
+  blink::WebString utf16(chars, env->GetStringLength(str));
+  env->ReleaseStringChars(str, chars);
+  return utf16.utf8();
+}
+
 }  // namespace
 
 GinJavaMethodInvocationHelper::GinJavaMethodInvocationHelper(
@@ -301,7 +310,7 @@ void GinJavaMethodInvocationHelper::InvokeMethod(jobject object,
         break;
       }
       result_wrapper.AppendString(
-          base::android::ConvertJavaStringToUTF8(scoped_java_string));
+          ConvertJavaStringToUTF8(env, scoped_java_string.obj()));
       break;
     }
     case JavaType::TypeObject: {