Support content scheme uri for Chrome on Android

base/android/content_uri_utils.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 "base/android/content_uri_utils.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
 #include "jni/ContentUriUtils_jni.h"
 
@@ skipping 17 matching lines @@
   JNIEnv* env = base::android::AttachCurrentThread();
   ScopedJavaLocalRef<jstring> j_uri =
       ConvertUTF8ToJavaString(env, content_uri.value());
   jint fd = Java_ContentUriUtils_openContentUriForRead(
       env, base::android::GetApplicationContext(), j_uri.obj());
   if (fd < 0)
     return File();
   return File(fd);
 }
 
+std::string GetContentUriMimeType(const FilePath& content_uri) {

[palmer, 2014/11/19 00:23:54]

The name "...uri" seems to conflict with the type FilePath. I'd expect a thing
named "...uri" to be a GURL or other URL/URI type. Is |content_uri| the path
component of a URL?

[qinmin, 2014/11/19 02:13:07]

There are some historic reasons. The previous patches about content URI are file
upload cases. We treat content URIs as a file, reading the content and get the
data. So content URI is currently only used in file related classes,  such as
FileStreamContext and FileUtil, e.g. Additionally, there are operations like
Open() on content URI to get file desciptors. That makes it more like a FilePath
rather than a GURL. So we just treat the "content://" scheme the same as a drive
letter on Windows.

+  JNIEnv* env = base::android::AttachCurrentThread();
+  ScopedJavaLocalRef<jstring> j_uri =
+      ConvertUTF8ToJavaString(env, content_uri.value());
+  ScopedJavaLocalRef<jstring> j_mime =
+      Java_ContentUriUtils_getMimeType(
+          env, base::android::GetApplicationContext(), j_uri.obj());
+  return base::android::ConvertJavaStringToUTF8(env, j_mime.obj());
+}
+
 }  // namespace base