diff --git a/libwvdrmengine/cdm/core/include/cdm_engine.h b/libwvdrmengine/cdm/core/include/cdm_engine.h
index f8501c11..453374cf 100644
--- a/libwvdrmengine/cdm/core/include/cdm_engine.h
+++ b/libwvdrmengine/cdm/core/include/cdm_engine.h
@@ -195,8 +195,9 @@ class CdmEngine {
   virtual bool IsKeyLoaded(const KeyId& key_id);
   virtual bool FindSessionForKey(const KeyId& key_id, CdmSessionId* sessionId);
 
-  // Used for notifying the Max-Res Engine of resolution changes
-  virtual void NotifyResolution(const CdmSessionId& session_id, uint32_t width,
+  // Used for notifying the Max-Res Engine of resolution changes.
+  // Return false if no match is found for session_id.
+  virtual bool NotifyResolution(const CdmSessionId& session_id, uint32_t width,
                                 uint32_t height);
 
   // Timer expiration method. This method is not re-entrant -- there can be
diff --git a/libwvdrmengine/cdm/core/src/cdm_engine.cpp b/libwvdrmengine/cdm/core/src/cdm_engine.cpp
index eb6859ee..7b13434b 100644
--- a/libwvdrmengine/cdm/core/src/cdm_engine.cpp
+++ b/libwvdrmengine/cdm/core/src/cdm_engine.cpp
@@ -1257,12 +1257,14 @@ bool CdmEngine::FindSessionForKey(const KeyId& key_id,
   return false;
 }
 
-void CdmEngine::NotifyResolution(const CdmSessionId& session_id, uint32_t width,
+bool CdmEngine::NotifyResolution(const CdmSessionId& session_id, uint32_t width,
                                  uint32_t height) {
   CdmSessionMap::iterator iter = sessions_.find(session_id);
   if (iter != sessions_.end()) {
     iter->second->NotifyResolution(width, height);
+    return true;
   }
+  return false;
 }
 
 bool CdmEngine::ValidateKeySystem(const CdmKeySystem& key_system) {