Rename producer methods to Start/StopDataSource

This is a pure rename with no functional changes.
This is in preparation for the fast-triggering
APIs described in the linked bug.

Bug: 116547201
Change-Id: Ie9d5d4793350c5e92acec5c805637db05e54e634
diff --git a/src/tracing/core/tracing_service_impl.h b/src/tracing/core/tracing_service_impl.h
index 62961b3..d50057e 100644
--- a/src/tracing/core/tracing_service_impl.h
+++ b/src/tracing/core/tracing_service_impl.h
@@ -83,8 +83,7 @@
     size_t shared_buffer_page_size_kb() const override;
 
     void OnTracingSetup();
-    void CreateDataSourceInstance(DataSourceInstanceID,
-                                  const DataSourceConfig&);
+    void StartDataSource(DataSourceInstanceID, const DataSourceConfig&);
     void TearDownDataSource(DataSourceInstanceID);
     void Flush(FlushRequestID, const std::vector<DataSourceInstanceID>&);
 
@@ -277,10 +276,10 @@
   TracingServiceImpl(const TracingServiceImpl&) = delete;
   TracingServiceImpl& operator=(const TracingServiceImpl&) = delete;
 
-  void CreateDataSourceInstance(const TraceConfig::DataSource&,
-                                const TraceConfig::ProducerConfig&,
-                                const RegisteredDataSource&,
-                                TracingSession*);
+  void StartDataSource(const TraceConfig::DataSource&,
+                       const TraceConfig::ProducerConfig&,
+                       const RegisteredDataSource&,
+                       TracingSession*);
 
   // Returns the next available ProducerID that is not in |producers_|.
   ProducerID GetNextProducerID();