Timeline: extract and rename TracingModelLoader into a file of its own

third_party/WebKit/LayoutTests/inspector/tracing/tracing-timeline-load.html

Index: third_party/WebKit/LayoutTests/inspector/tracing/tracing-timeline-load.html
diff --git a/third_party/WebKit/LayoutTests/inspector/tracing/tracing-timeline-load.html b/third_party/WebKit/LayoutTests/inspector/tracing/tracing-timeline-load.html
index da30717547baf54c73afdf857381f16686510d31..e4329235fdb7059cedc22e5557512528e6c849ba 100644
--- a/third_party/WebKit/LayoutTests/inspector/tracing/tracing-timeline-load.html
+++ b/third_party/WebKit/LayoutTests/inspector/tracing/tracing-timeline-load.html
@@ -26,9 +26,8 @@ function test()
             InspectorTest.assertEquals(JSON.stringify(expectedOutput), JSON.stringify(saveData), "saved data is not equal to restored");
         }
 
-        InspectorTest.override(model, "_createFileReader", createFileReader);
-
-        model.loadFromFile({}, new WebInspector.Progress());
+        InspectorTest.override(WebInspector.TimelineLoader, "_createFileReader", createFileReader);
+        WebInspector.TimelineLoader.loadFromFile(model, {}, new WebInspector.Progress());
     }
 
     function runTestOnMalformedInput(input)
@@ -46,8 +45,8 @@ function test()
             InspectorTest.assertTrue(model.isEmpty());
         }
 
-        InspectorTest.override(model, "_createFileReader", createFileReader);
-        model.loadFromFile({}, new WebInspector.Progress());
+        InspectorTest.override(WebInspector.TimelineLoader, "_createFileReader", createFileReader);
+        WebInspector.TimelineLoader.loadFromFile(model, {}, new WebInspector.Progress());
     }
 
     var data = [{"args":{"number":32},"cat":"__metadata","name":"num_cpus","ph":"M","pid":32127,"tid":0,"ts":0},