Provide error message if creating the CDM fails

Rather than using a generic error message when initialization
of a CDM fails, provide a specific error message.

BUG=407435
TEST=EME tests pass

Review URL: https://codereview.chromium.org/1128113004

Cr-Commit-Position: refs/heads/master@{#328809}

6 files changed, 23 insertions, 10 deletions

diff --git a/media/base/cdm_factory.h b/media/base/cdm_factory.h
index 8e0328a..0c9145d 100644
--- a/media/base/cdm_factory.h
+++ b/media/base/cdm_factory.h
@@ -15,7 +15,10 @@ class GURL;
 
 namespace media {
 
-using CdmCreatedCB = base::Callback<void(scoped_ptr<MediaKeys>)>;
+// Callback used when CDM is created. |error_message| only used if
+// MediaKeys is null (i.e. CDM can't be created).
+using CdmCreatedCB = base::Callback<void(scoped_ptr<MediaKeys>,
+                                         const std::string& error_message)>;
 
 class MEDIA_EXPORT CdmFactory {
  public:
diff --git a/media/blink/cdm_session_adapter.cc b/media/blink/cdm_session_adapter.cc
index 692eecc..f4f3906 100644
--- a/media/blink/cdm_session_adapter.cc
+++ b/media/blink/cdm_session_adapter.cc
@@ -36,7 +36,7 @@ void CdmSessionAdapter::CreateCdm(
     blink::WebContentDecryptionModuleResult result) {
   // Note: WebContentDecryptionModuleImpl::Create() calls this method without
   // holding a reference to the CdmSessionAdapter. Bind OnCdmCreated() with
-  // |this| instead of |weak_this| to prevent |this| from being desctructed.
+  // |this| instead of |weak_this| to prevent |this| from being destructed.
   base::WeakPtr<CdmSessionAdapter> weak_this = weak_ptr_factory_.GetWeakPtr();
   cdm_factory->Create(
       key_system, allow_distinctive_identifier, allow_persistent_state,
@@ -121,12 +121,13 @@ const std::string& CdmSessionAdapter::GetKeySystemUMAPrefix() const {
 void CdmSessionAdapter::OnCdmCreated(
     const std::string& key_system,
     blink::WebContentDecryptionModuleResult result,
-    scoped_ptr<MediaKeys> cdm) {
+    scoped_ptr<MediaKeys> cdm,
+    const std::string& error_message) {
   DVLOG(2) << __FUNCTION__;
   if (!cdm) {
     result.completeWithError(
         blink::WebContentDecryptionModuleExceptionNotSupportedError, 0,
-        "Failed to create the CDM instance.");
+        blink::WebString::fromUTF8(error_message));
     return;
   }
 
diff --git a/media/blink/cdm_session_adapter.h b/media/blink/cdm_session_adapter.h
index cc60143..28d26bb 100644
--- a/media/blink/cdm_session_adapter.h
+++ b/media/blink/cdm_session_adapter.h
@@ -111,7 +111,8 @@ class CdmSessionAdapter : public base::RefCounted<CdmSessionAdapter> {
   // Callback for CreateCdm().
   void OnCdmCreated(const std::string& key_system,
                     blink::WebContentDecryptionModuleResult result,
-                    scoped_ptr<MediaKeys> cdm);
+                    scoped_ptr<MediaKeys> cdm,
+                    const std::string& error_message);
 
   // Callbacks for firing session events.
   void OnSessionMessage(const std::string& session_id,
diff --git a/media/cdm/default_cdm_factory.cc b/media/cdm/default_cdm_factory.cc
index 4132a24..6b9714a 100644
--- a/media/cdm/default_cdm_factory.cc
+++ b/media/cdm/default_cdm_factory.cc
@@ -32,9 +32,15 @@ void DefaultCdmFactory::Create(
     const SessionKeysChangeCB& session_keys_change_cb,
     const SessionExpirationUpdateCB& session_expiration_update_cb,
     const CdmCreatedCB& cdm_created_cb) {
-  if (!security_origin.is_valid() || !CanUseAesDecryptor(key_system)) {
+  if (!security_origin.is_valid()) {
     base::ThreadTaskRunnerHandle::Get()->PostTask(
-        FROM_HERE, base::Bind(cdm_created_cb, nullptr));
+        FROM_HERE, base::Bind(cdm_created_cb, nullptr, "Invalid origin."));
+    return;
+  }
+  if (!CanUseAesDecryptor(key_system)) {
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE,
+        base::Bind(cdm_created_cb, nullptr, "Unsupported key system."));
     return;
   }
 
@@ -42,7 +48,7 @@ void DefaultCdmFactory::Create(
       new AesDecryptor(security_origin, session_message_cb, session_closed_cb,
                        session_keys_change_cb));
   base::ThreadTaskRunnerHandle::Get()->PostTask(
-      FROM_HERE, base::Bind(cdm_created_cb, base::Passed(&cdm)));
+      FROM_HERE, base::Bind(cdm_created_cb, base::Passed(&cdm), ""));
 }
 
 }  // namespace media
diff --git a/media/cdm/proxy_decryptor.cc b/media/cdm/proxy_decryptor.cc
index b8ba19c..d8dcd5a 100644
--- a/media/cdm/proxy_decryptor.cc
+++ b/media/cdm/proxy_decryptor.cc
@@ -89,7 +89,8 @@ void ProxyDecryptor::CreateCdm(CdmFactory* cdm_factory,
 void ProxyDecryptor::OnCdmCreated(const std::string& key_system,
                                   const GURL& security_origin,
                                   const CdmContextReadyCB& cdm_context_ready_cb,
-                                  scoped_ptr<MediaKeys> cdm) {
+                                  scoped_ptr<MediaKeys> cdm,
+                                  const std::string& /* error_message */) {
   is_creating_cdm_ = false;
 
   if (!cdm) {
diff --git a/media/cdm/proxy_decryptor.h b/media/cdm/proxy_decryptor.h
index 9a17a98..09a94e3 100644
--- a/media/cdm/proxy_decryptor.h
+++ b/media/cdm/proxy_decryptor.h
@@ -76,7 +76,8 @@ class MEDIA_EXPORT ProxyDecryptor {
   void OnCdmCreated(const std::string& key_system,
                     const GURL& security_origin,
                     const CdmContextReadyCB& cdm_context_ready_cb,
-                    scoped_ptr<MediaKeys> cdm);
+                    scoped_ptr<MediaKeys> cdm,
+                    const std::string& error_message);
 
   void GenerateKeyRequestInternal(EmeInitDataType init_data_type,
                                   const std::vector<uint8>& init_data);