Fix media timeline so that thumb never exceeds buffered data

media/base/mock_filters.cc

Index: media/base/mock_filters.cc
diff --git a/media/base/mock_filters.cc b/media/base/mock_filters.cc
index 484fe8dc459b3e60b14a58359d9fffee594ba46f..9c116b7c399cf7648ddc6ce15603518024d9e618 100644
--- a/media/base/mock_filters.cc
+++ b/media/base/mock_filters.cc
@@ -176,6 +176,11 @@ void RunPipelineStatusCB3(::testing::Unused, const PipelineStatusCB& callback,
   callback.Run(PIPELINE_OK);
 }
 
+void RunPipelineStatusCB4(::testing::Unused, const PipelineStatusCB& callback,
+                          ::testing::Unused, ::testing::Unused) {
+  callback.Run(PIPELINE_OK);
+}
+
 void RunStopFilterCallback(const base::Closure& callback) {
   callback.Run();
 }