[Android] Introduce a Java wrapper for TemplateUrlService.

base/android/jni_map.h

+// 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.
+
+#ifndef BASE_ANDROID_JNI_MAP_H_
+#define BASE_ANDROID_JNI_MAP_H_
+
+#include <jni.h>
+#include <map>
+#include <string>
+
+#include "base/android/scoped_java_ref.h"
+#include "base/base_export.h"
+#include "base/string16.h"
+
+namespace base {
+namespace android {
+
+// Convert a std::map<std::string, string16> to a Java HashMap<String, String>
+BASE_EXPORT ScopedJavaLocalRef<jobject> ConvertMapToJavaMap(

[bulach, 2013/02/22 12:49:25]

..ToJavaHashMap (and below) ?

also, this is converting only a <String, String>, which goes back to my point:
we've survived this long without passing a "transparent" map. I still think that
having a "@CalledByNative / native setKeyValue()" where needed rather than
allowing java objects to be inspected (and provided by base) would probably be
simpler..

I mean, this is not generic enough and the next person that needs <String, Int>
or whatever other combination of key-value types, would have to hack their way
around in base, plus their own code, right?

matching the generic in java and the template type in c++ is probably going to
be more painful than ad-hoc, type safe "setKeyValues"...

I appreciate the need to "marshall a map", I'm just saying we either make it
more generic, or we keep it private to the places that need them... 

otoh, jni_array.h has a bunch of utilities methods. granted, one dimension is
easier :) so if you want to specify in here "StringString" in the name of the
functions, that would probably be more inline with the array methods... wdyt?

+    JNIEnv* env,
+    const std::map<std::string, string16>& cmap);
+
+// Convert a Java subclass of map to std::map. Assumes values are string16.
+// Any null key/values are dropped.
+BASE_EXPORT std::map<std::string, string16> ConvertJavaMapToMap(JNIEnv* env,
+                                                                jobject jmap);
+
+bool RegisterMap(JNIEnv* env);
+
+}  // namespace android
+}  // namespace base
+
+#endif  // BASE_ANDROID_JNI_MAP_H_