Add offline storage manager and manifest parser.

This contains two major parts: the Storage class, which manages
storing, listing, and deleting the stored content, and the offline
manifest parser, which loads the stored content into a manifest so the
Player can play it.

This does not include support for storing encrypted content.  The
EME sessions will not be stored properly and will fail to play.

Issue shaka-project#343

Change-Id: I7ecb3400391ec8100155aa972f9b09bb7ae24d9d

build/types/offline

@@ -1,3 +1,7 @@
 # The offline storage system and manifest parser plugin.
 
 +../../lib/offline/db_engine.js
++../../lib/offline/download_manager.js
++../../lib/offline/offline_manifest_parser.js
++../../lib/offline/offline_scheme.js
++../../lib/offline/storage.js

externs/shaka/offline.js

@@ -0,0 +1,217 @@
+/**
+ * @license
+ * Copyright 2016 Google Inc.
+ *
+ * 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.
+ */
+
+
+/** @externs */
+
+
+/**
+ * @typedef {{
+ *   basic: boolean,
+ *   encrypted: !Object.<string, boolean>
+ * }}
+ *
+ * @property {boolean} basic
+ *   True if offline is usable at all.
+ * @property {!Object.<string, boolean>} encrypted
+ *   A map of key system name to whether it supports offline playback.
+ */
+shakaExtern.OfflineSupport;
+
+
+/**
+ * @typedef {{
+ *   trackSelectionCallback:
+ *       function(!Array.<shakaExtern.Track>):!Array.<shakaExtern.Track>,
+ *   progressCallback: function(shakaExtern.StoredContent,number)
+ * }}
+ *
+ * @property {function(!Array.<shakaExtern.Track>):!Array.<shakaExtern.Track>}
+ *     trackSelectionCallback
+ *   Called inside store() to determine which tracks to save from a manifest.
+ *   It is passed an array of Tracks from the manifest and it should return
+ *   an array of the tracks to store.  This is called for each Period in the
+ *   manifest (in order).
+ * @property {function(shakaExtern.StoredContent,number)} progressCallback
+ *   Called inside store() to give progress info back to the app.  It is given
+ *   the current manifest being stored and the progress of it being stored.
+ */
+shakaExtern.OfflineConfiguration;
+
+
+/**
+ * @typedef {{
+ *   offlineUri: string,
+ *   originalManifestUri: string,
+ *   duration: number,
+ *   size: number,
+ *   tracks: !Array.<shakaExtern.Track>,
+ *   appMetadata: Object
+ * }}
+ *
+ * @property {string} offlineUri
+ *   An offline URI to access the content.  This can be passed directly to
+ *   Player.
+ * @property {string} originalManifestUri
+ *   The original manifest URI of the content stored.
+ * @property {number} duration
+ *   The duration of the content, in seconds.
+ * @property {number} size
+ *   The size of the content, in bytes.
+ * @property {!Array.<shakaExtern.Track>} tracks
+ *   The tracks that are stored.  This only lists those found in the first
+ *   Period.
+ * @property {Object} appMetadata
+ *   The metadata passed to store().
+ */
+shakaExtern.StoredContent;
+
+
+/**
+ * @typedef {{
+ *   key: number,
+ *   originalManifestUri: string,
+ *   duration: number,
+ *   size: number,
+ *   periods: !Array.<shakaExtern.PeriodDB>,
+ *   sessionIds: !Array.<string>,
+ *   drmInfo: ?shakaExtern.DrmInfo,
+ *   appMetadata: Object
+ * }}
+ *
+ * @property {number} key
+ *   The key that uniquely identifies the manifest.
+ * @property {string} originalManifestUri
+ *   The URI that the manifest was originally loaded from.
+ * @property {number} duration
+ *   The total duration of the media, in seconds.
+ * @property {number} size
+ *   The total size of all stored segments, in bytes.
+ * @property {!Array.<shakaExtern.PeriodDB>} periods
+ *   The Periods that are stored.
+ * @property {!Array.<string>} sessionIds
+ *   The DRM offline session IDs for the media.
+ * @property {?shakaExtern.DrmInfo} drmInfo
+ *   The DRM info used to initialize EME.
+ * @property {Object} appMetadata
+ *   A metadata object passed from the application.
+ */
+shakaExtern.ManifestDB;
+
+
+/**
+ * @typedef {{
+ *   startTime: number,
+ *   streams: !Array.<shakaExtern.StreamDB>
+ * }}
+ *
+ * @property {number} startTime
+ *   The start time of the period, in seconds.
+ * @property {!Array.<shakaExtern.StreamDB>} streams
+ *   The streams that define the Period.
+ */
+shakaExtern.PeriodDB;
+
+
+/**
+ * @typedef {{
+ *   id: number,
+ *   primary: boolean,
+ *   presentationTimeOffset: number,
+ *   contentType: string,
+ *   mimeType: string,
+ *   codecs: string,
+ *   kind: (string|undefined),
+ *   language: string,
+ *   width: ?number,
+ *   height: ?number,
+ *   initSegmentUri: ?string,
+ *   encrypted: boolean,
+ *   keyId: ?string,
+ *   segments: !Array.<shakaExtern.SegmentDB>
+ * }}
+ *
+ * @property {number} id
+ *   The unique id of the stream.
+ * @property {boolean} primary
+ *   Whether the stream set was primary.
+ * @property {number} presentationTimeOffset
+ *   The presentation time offset of the stream.
+ * @property {string} contentType
+ *   The type of the stream, 'audio', 'text', or 'video'.
+ * @property {string} mimeType
+ *   The MIME type of the stream.
+ * @property {string} codecs
+ *   The codecs of the stream.
+ * @property {(string|undefined)} kind
+ *   The kind of text stream; undefined for audio/video.
+ * @property {string} language
+ *   The language of the stream; '' for video.
+ * @property {?number} width
+ *   The width of the stream; null for audio/text.
+ * @property {?number} height
+ *   The height of the stream; null for audio/text.
+ * @property  {?string} initSegmentUri
+ *   The offline URI where the init segment is found; null if no init segment.
+ * @property {boolean} encrypted
+ *   Whether this stream is encrypted.
+ * @property {?string} keyId
+ *   The key ID this stream is encrypted with.
+ * @property {!Array.<shakaExtern.SegmentDB>} segments
+ *   An array of segments that make up the stream
+ */
+shakaExtern.StreamDB;
+
+
+/**
+ * @typedef {{
+ *   startTime: number,
+ *   endTime: number,
+ *   uri: string
+ * }}
+ *
+ * @property {number} startTime
+ *   The start time of the segment, in seconds from the start of the Period.
+ * @property {number} endTime
+ *   The end time of the segment, in seconds from the start of the Period.
+ * @property {string} uri
+ *   The offline URI where the segment is found.
+ */
+shakaExtern.SegmentDB;
+
+
+/**
+ * @typedef {{
+ *   key: number,
+ *   data: !ArrayBuffer,
+ *   manifestKey: number,
+ *   streamNumber: number,
+ *   segmentNumber: number
+ * }}
+ *
+ * @property {number} key
+ *   A key that uniquely describes the segment.
+ * @property {!ArrayBuffer} data
+ *   The data contents of the segment.
+ * @property {number} manifestKey
+ *   The key of the manifest this belongs to.
+ * @property {number} streamNumber
+ *   The index of the stream this belongs to.
+ * @property {number} segmentNumber
+ *   The index of the segment within the stream.
+ */
+shakaExtern.SegmentDataDB;