Restore the active program after transform feedback

src/libANGLE/renderer/gl/StateManagerGL.h

@@ -173,6 +173,7 @@ class StateManagerGL final : angle::NonCopyable
         }
     }
 
+    GLuint getProgramID() const { return mProgram; }
     GLuint getVertexArrayID() const { return mVAO; }
     GLuint getFramebufferID(angle::FramebufferBinding binding) const
     {

src/libANGLE/renderer/gl/TransformFeedbackGL.cpp

@@ -131,8 +131,14 @@ void TransformFeedbackGL::syncActiveState(const gl::Context *context,
         }
         else
         {
+            // Implementations disagree about what should happen if a different program is bound
+            // when calling EndTransformFeedback. We avoid the ambiguity by always re-binding the
+            // program associated with this transform feedback.
+            GLuint previousProgram = mStateManager->getProgramID();
             mStateManager->useProgram(mActiveProgram);
             mFunctions->endTransformFeedback();
+            // Restore the current program if we changed it.
+            mStateManager->useProgram(previousProgram);
         }
     }
 }