fix: Creates an InMemoryMemoryService within the EvaluationGenerator

Merge https://github.com/google/adk-python/pull/2263

Addresses #2084

COPYBARA_INTEGRATE_REVIEW=https://github.com/google/adk-python/pull/2263 from sjhatfield:main 8d6fca48437f151c34b2766ea4813a777bafcabd
PiperOrigin-RevId: 792336301

src/google/adk/evaluation/evaluation_generator.py

@@ -24,6 +24,8 @@ from pydantic import BaseModel
 from ..agents.llm_agent import Agent
 from ..artifacts.base_artifact_service import BaseArtifactService
 from ..artifacts.in_memory_artifact_service import InMemoryArtifactService
+from ..memory.base_memory_service import BaseMemoryService
+from ..memory.in_memory_memory_service import InMemoryMemoryService
 from ..runners import Runner
 from ..sessions.base_session_service import BaseSessionService
 from ..sessions.in_memory_session_service import InMemorySessionService
@@ -142,11 +144,15 @@ class EvaluationGenerator:
       session_id: Optional[str] = None,
       session_service: Optional[BaseSessionService] = None,
       artifact_service: Optional[BaseArtifactService] = None,
+      memory_service: Optional[BaseMemoryService] = None,
   ) -> list[Invocation]:
     """Scrapes the root agent given the list of Invocations."""
     if not session_service:
       session_service = InMemorySessionService()
 
+    if not memory_service:
+      memory_service = InMemoryMemoryService()
+
     app_name = (
         initial_session.app_name if initial_session else "EvaluationGenerator"
     )
@@ -168,6 +174,7 @@ class EvaluationGenerator:
         agent=root_agent,
         artifact_service=artifact_service,
         session_service=session_service,
+        memory_service=memory_service,
     )
 
     # Reset agent state for each query