arc: Use the MIME type returned by the container to handle content URLs

components/arc/test/fake_file_system_instance.cc

 // Copyright 2016 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 "components/arc/test/fake_file_system_instance.h"
 
 #include <string.h>
 #include <unistd.h>
 
 #include <utility>
@@ skipping 46 matching lines @@
   document->last_modified = doc.last_modified;
   return document;
 }
 
 }  // namespace
 
 FakeFileSystemInstance::File::File(const File& that) = default;
 
 FakeFileSystemInstance::File::File(const std::string& url,
                                    const std::string& content,
+                                   const std::string& mime_type,
                                    Seekable seekable)
-    : url(url), content(content), seekable(seekable) {}
+    : url(url), content(content), mime_type(mime_type), seekable(seekable) {}
 
 FakeFileSystemInstance::File::~File() = default;
 
 FakeFileSystemInstance::Document::Document(const Document& that) = default;
 
 FakeFileSystemInstance::Document::Document(
     const std::string& authority,
     const std::string& document_id,
     const std::string& parent_document_id,
     const std::string& display_name,
@@ skipping 84 matching lines @@
   if (iter == files_.end()) {
     base::ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE,
                                                   base::Bind(callback, -1));
     return;
   }
   const File& file = iter->second;
   base::ThreadTaskRunnerHandle::Get()->PostTask(
       FROM_HERE, base::Bind(callback, file.content.size()));
 }
 
+void FakeFileSystemInstance::GetMimeType(const std::string& url,
+                                         const GetMimeTypeCallback& callback) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  auto iter = files_.find(url);
+  if (iter == files_.end()) {
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE, base::Bind(callback, base::Optional<std::string>()));

[dcheng, 2017/06/01 11:06:44]

Ditto: prefer base::nullopt

[hashimoto, 2017/06/01 11:30:16]

Done.

+    return;
+  }
+  const File& file = iter->second;
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, base::Bind(callback, file.mime_type));
+}
+
 void FakeFileSystemInstance::OpenFileToRead(
     const std::string& url,
     const OpenFileToReadCallback& callback) {
   DCHECK(thread_checker_.CalledOnValidThread());
   auto iter = files_.find(url);
   if (iter == files_.end()) {
     base::ThreadTaskRunnerHandle::Get()->PostTask(
         FROM_HERE, base::Bind(callback, base::Passed(mojo::ScopedHandle())));
     return;
   }
@@ skipping 75 matching lines @@
                                                 base::Bind(callback, true));
 }
 
 void FakeFileSystemInstance::RequestMediaScan(
     const std::vector<std::string>& paths) {
   DCHECK(thread_checker_.CalledOnValidThread());
   // Do nothing and pretend we scaned them.
 }
 
 }  // namespace arc