Add an IPC to return the platform supported key-system names in Android.

components/cdm/browser/cdm_message_filter_android.cc

Index: components/cdm/browser/cdm_message_filter_android.cc
diff --git a/components/cdm/browser/cdm_message_filter_android.cc b/components/cdm/browser/cdm_message_filter_android.cc
index 2bda86078edf434c9f5dc759f716cb77ad7f2ab1..62d027638c2cbfad1499472b5e089b4c2e7d55de 100644
--- a/components/cdm/browser/cdm_message_filter_android.cc
+++ b/components/cdm/browser/cdm_message_filter_android.cc
@@ -5,12 +5,15 @@
 #include "components/cdm/browser/cdm_message_filter_android.h"
 
 #include <string>
+#include <vector>
 
 #include "components/cdm/common/cdm_messages_android.h"
 #include "ipc/ipc_message_macros.h"
 #include "media/base/android/media_codec_bridge.h"
 #include "media/base/android/media_drm_bridge.h"
 
+#include "widevine_cdm_version.h"  // In SHARED_INTERMEDIATE_DIR.
+
 using content::BrowserThread;
 using content::SupportedCodecs;
 using media::MediaCodecBridge;
@@ -66,15 +69,24 @@ static SupportedCodecs GetSupportedCodecs(
 }
 
 CdmMessageFilterAndroid::CdmMessageFilterAndroid()

[ddorwin, 2014/06/10 18:48:03]

This is used by Chrome and the next one is only used by AW, right?

[ycheo (away), 2014/06/11 00:08:22]

That's my original intention.

-    : BrowserMessageFilter(EncryptedMediaMsgStart) {}
+    : BrowserMessageFilter(EncryptedMediaMsgStart) {
+  key_systems_.push_back(kWidevineKeySystem);

[ddorwin, 2014/06/10 18:48:03]

If we need special handling for Chrome, why not just pass this in from Chrome
and have a single constructor? This also avoids including Widevine directly
here.

[ycheo (away), 2014/06/11 00:08:21]

Removed.

+}
+
+CdmMessageFilterAndroid::CdmMessageFilterAndroid(

[ddorwin, 2014/06/10 18:48:04]

This is never used.

[ycheo (away), 2014/06/11 00:08:22]

Removed.

+    const std::vector<std::string> key_systems)
+    : BrowserMessageFilter(EncryptedMediaMsgStart),
+      key_systems_(key_systems) {}
 
 CdmMessageFilterAndroid::~CdmMessageFilterAndroid() {}
 
 bool CdmMessageFilterAndroid::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(CdmMessageFilterAndroid, message)
-    IPC_MESSAGE_HANDLER(ChromeViewHostMsg_GetSupportedKeySystems,
-                        OnGetSupportedKeySystems)
+    IPC_MESSAGE_HANDLER(CdmHostMsg_GetSupportedKeySystem,

[ddorwin, 2014/06/10 18:48:03]

I'm not sure CdmHostMsg is correct. It is not a message to a CDM host.
(If this changes, the CL description needs to be updated.)

[ycheo (away), 2014/06/11 00:08:22]

Reverted the prefix to ChromeViewHostMsg.

+                        OnGetSupportedKeySystem)
+    IPC_MESSAGE_HANDLER(CdmHostMsg_GetAllSupportedKeySystemNames,
+                        OnGetAllSupportedKeySystemNames)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
@@ -83,11 +95,13 @@ bool CdmMessageFilterAndroid::OnMessageReceived(const IPC::Message& message) {
 void CdmMessageFilterAndroid::OverrideThreadForMessage(
     const IPC::Message& message, BrowserThread::ID* thread) {
   // Move the IPC handling to FILE thread as it is not very cheap.
-  if (message.type() == ChromeViewHostMsg_GetSupportedKeySystems::ID)
+  if (message.type() == CdmHostMsg_GetSupportedKeySystem::ID ||
+      message.type() == CdmHostMsg_GetAllSupportedKeySystemNames) {

[ddorwin, 2014/06/10 18:48:04]

This one is cheap - it just returns a list, right?

[ycheo (away), 2014/06/11 00:08:21]

Correct. Removed this from the condition.

     *thread = BrowserThread::FILE;
+  }
 }
 
-void CdmMessageFilterAndroid::OnGetSupportedKeySystems(
+void CdmMessageFilterAndroid::OnGetSupportedKeySystem(

[ddorwin, 2014/06/10 18:48:04]

This should probably be something like OnGetKeySystemInfo, though there is an
element of "support" and query. OnQueryKeySystemInfo?

[ycheo (away), 2014/06/11 00:08:22]

Thanks for the suggestion.

     const SupportedKeySystemRequest& request,
     SupportedKeySystemResponse* response) {
   if (!response) {
@@ -110,4 +124,9 @@ void CdmMessageFilterAndroid::OnGetSupportedKeySystems(
   response->non_compositing_codecs = GetSupportedCodecs(request, false);
 }
 
+void CdmMessageFilterAndroid::OnGetAllSupportedKeySystemNames(

[ddorwin, 2014/06/10 18:48:04]

If this was OnGetPlatform... then you wouldn't need line 73 or the related
include and you could avoid having to skip widevine in the caller
(android_key_systems.cc).

[ycheo (away), 2014/06/11 00:08:21]

Done.

+    std::vector<std::string>* key_systems) {
+  *key_systems = key_systems_;

[ddorwin, 2014/06/10 18:48:04]

It seems this information should come from the same place as
MediaDrmBridge::IsKeySystemSupported().

[ycheo (away), 2014/06/11 00:08:21]

Added a method MediaDrmBridge::GetPlatformKeySystemNames().

+}
+
 }  // namespace cdm