Unhide the android.media.[Media]DataSource interface.

This allows apps to implement MediaDataSource, which is modeled on
stagefright's DataSource, to supply media data to the framework. This
was already implemented for MediaExtractor, but it was renamed from
DataSource.

MediaExtractor, MediaPlayer and MediaMetadataRetriever each have a new
overload: #setDataSource(android.media.MediaDataSource)

Only NuPlayer supports this new data source.

The change introduces:
 * IDataSource:        The binder interface for DataSource.
 * JMediaDataSource:   The native counterpart to the java interface. It
                       implements IDataSource.
 * CallbackDataSource: A stagefright DataSource that wraps an
                       IDataSource.

Change-Id: Ib3c944b49cc8a792c8eb9c85e5015c07f298ebc1
diff --git a/include/media/IDataSource.h b/include/media/IDataSource.h
new file mode 100644
index 0000000..07e46f7
--- /dev/null
+++ b/include/media/IDataSource.h
@@ -0,0 +1,61 @@
+/*
+ * Copyright 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_IDATASOURCE_H
+#define ANDROID_IDATASOURCE_H
+
+#include <binder/IInterface.h>
+#include <media/stagefright/foundation/ABase.h>
+#include <utils/Errors.h>
+
+namespace android {
+
+class IMemory;
+
+// A binder interface for implementing a stagefright DataSource remotely.
+class IDataSource : public IInterface {
+public:
+    DECLARE_META_INTERFACE(DataSource);
+
+    // Get the memory that readAt writes into.
+    virtual sp<IMemory> getIMemory() = 0;
+    // Read up to |size| bytes into the memory returned by getIMemory(). Returns
+    // the number of bytes read, or -1 on error. |size| must not be larger than
+    // the buffer.
+    virtual ssize_t readAt(off64_t offset, size_t size) = 0;
+    // Get the size, or -1 if the size is unknown.
+    virtual status_t getSize(off64_t* size) = 0;
+    // This should be called before deleting |this|. The other methods may
+    // return errors if they're called after calling close().
+    virtual void close() = 0;
+
+private:
+    DISALLOW_EVIL_CONSTRUCTORS(IDataSource);
+};
+
+// ----------------------------------------------------------------------------
+
+class BnDataSource : public BnInterface<IDataSource> {
+public:
+    virtual status_t onTransact(uint32_t code,
+                                const Parcel& data,
+                                Parcel* reply,
+                                uint32_t flags = 0);
+};
+
+}; // namespace android
+
+#endif // ANDROID_IDATASOURCE_H