EME on Android: Improve accuracy of Key System availability.

media/base/android/media_drm_bridge.cc

Index: media/base/android/media_drm_bridge.cc
diff --git a/media/base/android/media_drm_bridge.cc b/media/base/android/media_drm_bridge.cc
index 0633c31b98603f1f4e1b0ad99f291a1b261c6635..ab9999103907e50c49f70ef47a2867173b149936 100644
--- a/media/base/android/media_drm_bridge.cc
+++ b/media/base/android/media_drm_bridge.cc
@@ -26,6 +26,7 @@
 #include "base/thread_task_runner_handle.h"
 #include "jni/MediaDrmBridge_jni.h"
 #include "media/base/android/media_client_android.h"
+#include "media/base/android/media_codec_util.h"
 #include "media/base/android/media_drm_bridge_delegate.h"
 #include "media/base/android/provision_fetcher.h"
 #include "media/base/cdm_key_information.h"
@@ -174,8 +175,12 @@ base::LazyInstance<KeySystemManager>::Leaky g_key_system_manager =
 // resolved.
 bool IsKeySystemSupportedWithTypeImpl(const std::string& key_system,
                                       const std::string& container_mime_type) {
-  if (!MediaDrmBridge::IsAvailable())
+  DCHECK(MediaDrmBridge::IsAvailable());
+
+  if (key_system.empty()) {
+    NOTREACHED();
     return false;
+  }
 
   UUID scheme_uuid = g_key_system_manager.Get().GetUUID(key_system);
   if (scheme_uuid.empty())
@@ -215,10 +220,7 @@ std::string GetSecurityLevelString(
   return "";
 }
 
-}  // namespace
-
-// static
-bool MediaDrmBridge::IsAvailable() {
+bool AreMediaDrmApisAvailable() {
   if (base::android::BuildInfo::GetInstance()->sdk_int() < 19)
     return false;
 
@@ -233,6 +235,18 @@ bool MediaDrmBridge::IsAvailable() {
   return true;
 }
 
+}  // namespace
+
+// MediaDrm is not generally usable without MediaCodec. Thus, both the MediaDrm
+// APIs and MediaCodec APIs must be enabled and not blacklisted.
+// static
+bool MediaDrmBridge::IsAvailable() {
+  if (!AreMediaDrmApisAvailable())
+    return false;
+
+  return MediaCodecUtil::IsMediaCodecAvailable();

[xhwang, 2016/03/02 06:57:08]

nit: how about:

return AreMediaDrmApisAvailable() && MediaCodecUtil::IsMediaCodecAvailable();

[ddorwin, 2016/03/02 21:11:53]

Done.

+}
+
 // static
 bool MediaDrmBridge::RegisterMediaDrmBridge(JNIEnv* env) {
   return RegisterNativesImpl(env);
@@ -240,7 +254,9 @@ bool MediaDrmBridge::RegisterMediaDrmBridge(JNIEnv* env) {
 
 // static
 bool MediaDrmBridge::IsKeySystemSupported(const std::string& key_system) {
-  DCHECK(!key_system.empty());
+  if (!MediaDrmBridge::IsAvailable())
+    return false;
+
   return IsKeySystemSupportedWithTypeImpl(key_system, "");
 }
 
@@ -248,17 +264,24 @@ bool MediaDrmBridge::IsKeySystemSupported(const std::string& key_system) {
 bool MediaDrmBridge::IsKeySystemSupportedWithType(
     const std::string& key_system,
     const std::string& container_mime_type) {
-  DCHECK(!key_system.empty() && !container_mime_type.empty());
+  DCHECK(!container_mime_type.empty()) << "Call IsKeySystemSupported instead";
+
+  if (!MediaDrmBridge::IsAvailable())
+    return false;
+
   return IsKeySystemSupportedWithTypeImpl(key_system, container_mime_type);
 }
 
 // static
 std::vector<std::string> MediaDrmBridge::GetPlatformKeySystemNames() {
+  if (!MediaDrmBridge::IsAvailable())
+    return std::vector<std::string>();
+
   return g_key_system_manager.Get().GetPlatformKeySystemNames();
 }
 
 // static
-scoped_refptr<MediaDrmBridge> MediaDrmBridge::Create(
+scoped_refptr<MediaDrmBridge> MediaDrmBridge::CreateInternal(
     const std::string& key_system,
     SecurityLevel security_level,
     const CreateFetcherCB& create_fetcher_cb,
@@ -267,10 +290,8 @@ scoped_refptr<MediaDrmBridge> MediaDrmBridge::Create(
     const LegacySessionErrorCB& legacy_session_error_cb,
     const SessionKeysChangeCB& session_keys_change_cb,
     const SessionExpirationUpdateCB& session_expiration_update_cb) {
-  DVLOG(1) << __FUNCTION__;
-
-  if (!IsAvailable())
-    return nullptr;
+  // All paths requires the MediaDrmApis.
+  DCHECK(AreMediaDrmApisAvailable());
 
   UUID scheme_uuid = g_key_system_manager.Get().GetUUID(key_system);
   if (scheme_uuid.empty())
@@ -288,12 +309,37 @@ scoped_refptr<MediaDrmBridge> MediaDrmBridge::Create(
 }
 
 // static
+scoped_refptr<MediaDrmBridge> MediaDrmBridge::Create(
+    const std::string& key_system,
+    SecurityLevel security_level,
+    const CreateFetcherCB& create_fetcher_cb,
+    const SessionMessageCB& session_message_cb,
+    const SessionClosedCB& session_closed_cb,
+    const LegacySessionErrorCB& legacy_session_error_cb,
+    const SessionKeysChangeCB& session_keys_change_cb,
+    const SessionExpirationUpdateCB& session_expiration_update_cb) {
+  DVLOG(1) << __FUNCTION__;
+
+  if (!IsAvailable())
+    return nullptr;
+
+  return CreateInternal(key_system, security_level, create_fetcher_cb,
+                        session_message_cb, session_closed_cb,
+                        legacy_session_error_cb, session_keys_change_cb,
+                        session_expiration_update_cb);
+}
+
+// static
 scoped_refptr<MediaDrmBridge> MediaDrmBridge::CreateWithoutSessionSupport(
     const std::string& key_system,
     SecurityLevel security_level,
     const CreateFetcherCB& create_fetcher_cb) {
   DVLOG(1) << __FUNCTION__;
 
+  // Sessions won't be used so decoding capability is not required.
+  if (!AreMediaDrmApisAvailable())
+    return nullptr;
+
   return MediaDrmBridge::Create(key_system, security_level, create_fetcher_cb,
                                 SessionMessageCB(), SessionClosedCB(),
                                 LegacySessionErrorCB(), SessionKeysChangeCB(),