Adds MediaClientAndroid to support embedder/MediaDrmBridge interaction.

android_webview/browser/aw_media_client_android.cc

+// Copyright 2015 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 "android_webview/browser/aw_media_client_android.h"
+
+#include <utility>
+
+#include "base/stl_util.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
+
+namespace android_webview {
+
+namespace {
+
+const size_t kGUIDLength = 36U;
+
+std::pair<std::string, media::UUID> CreateMappingFromString(
+    const std::string& key_system_uuid_mapping) {
+  std::vector<std::string> tokens;
+  Tokenize(key_system_uuid_mapping, ",", &tokens);
+
+  std::string key_system;
+  base::TrimWhitespaceASCII(tokens[0], base::TRIM_ALL, &key_system);
+
+  std::vector<uint8_t> uuid;
+  std::string guid(tokens[1]);

[boliu, 2015/04/29 19:24:25]

Is it safe to assume key_system_uuid_mapping can always to tokenized correctly,
or parsed as hex string correctly?

Previous java code catches any parsing exceptions. This will just crash.

[gunsch, 2015/04/29 20:29:43]

I was hoping you could answer that: I don't really have insight into what
content AW passes here. But since this string in built into the package itself
and not user-provided, ISTM that it's actually a bug to be fixed if anyone uses
a resource string that isn't correct.

That said, it may be better to keep the behavior to log an error and move on, so
I've adjusted the code to do that.

[boliu, 2015/04/29 23:15:44]

It comes from a resource that individual devices can then override/add to. Eg
apparently nexus player supports microsoft playready:
https://android.googlesource.com/device/asus/fugu/+/lollipop-release/overlay/...
Yeah, better not crash first.

+  DCHECK(guid.length() == kGUIDLength);
+  base::RemoveChars(guid, "-", &guid);
+  base::HexStringToBytes(guid, &uuid);
+
+  return std::make_pair(key_system, uuid);
+}
+
+}  // namespace
+
+AwMediaClientAndroid::AwMediaClientAndroid(
+    const std::vector<std::string>& key_system_uuid_mappings)
+    : key_system_uuid_mappings_(key_system_uuid_mappings) {
+}
+
+AwMediaClientAndroid::~AwMediaClientAndroid() {
+}
+
+void AwMediaClientAndroid::AddKeySystemUUIDMappings(KeySystemUuidMap* map) {
+  for (const std::string& key_system_uuid_mapping : key_system_uuid_mappings_) {
+    std::pair<std::string, media::UUID> mapping =
+        CreateMappingFromString(key_system_uuid_mapping);
+    (*map)[mapping.first] = mapping.second;

[boliu, 2015/04/29 19:24:25]

map->insert?

[gunsch, 2015/04/29 20:29:44]

Done.

+  }
+}
+
+media::MediaDrmBridgeDelegate*
+AwMediaClientAndroid::GetMediaDrmBridgeDelegate(
+    const media::UUID& scheme_uuid) {
+  if (scheme_uuid == widevine_delegate_.GetUUID())
+    return &widevine_delegate_;
+  return nullptr;

[boliu, 2015/04/29 19:24:25]

Pure question on my part since I don't actually know the whole system. So looks
like AddKeySystemUUIDMappings can potentially advertise other systems with
different UUIDs, but here there's only a delegate for the widevine one? So how
does that magically work? Was it behaving like this before this patch?

[gunsch, 2015/04/29 20:29:43]

This patch shouldn't change any user-facing behavior from before.

KeySystemUUIDMappings is used to make sure all key systems are still registered.

Delegates are specifically to add additional functionality. For example, the
Widevine delegate's primary purpose is to strip the PSSH box and pass only the
license data itself to the  MediaDrm instance.

+}
+
+}  // namespace android_webview