gpu benchmarking swipe for touchpad

content/renderer/gpu/gpu_benchmarking_extension.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_GPU_GPU_BENCHMARKING_EXTENSION_H_
 #define CONTENT_RENDERER_GPU_GPU_BENCHMARKING_EXTENSION_H_
 
 #include "base/macros.h"
 #include "gin/wrappable.h"
 
@@ skipping 30 matching lines @@
   void SetNeedsDisplayOnAllLayers();
   void SetRasterizeOnlyVisibleContent();
   void PrintToSkPicture(v8::Isolate* isolate, const std::string& dirname);
   void PrintPagesToSkPictures(v8::Isolate* isolate,
                               const std::string& filename);
   void PrintPagesToXPS(v8::Isolate* isolate,
                          const std::string& filename);
   bool GestureSourceTypeSupported(int gesture_source_type);
   bool SmoothScrollBy(gin::Arguments* args);
   bool SmoothDrag(gin::Arguments* args);
+
+  // This function generates a scroll followed by a fling. The default input
+  // source is touch; Source, velocity_x, and velocity_y are extra args that
+  // are necessary for a touchpad fling. Note that swipe only works when
+  // threaded compositing is enabled.

[bokan, 2017/03/10 14:41:57]

Is this because of a difference in how main thread flings are handled?

[sahel, 2017/03/10 21:51:41]

I tried to debug it to see what the cause is. It seems like when a GFS is
handled by main thread, the call back function of swipe is never called.

One can still use swipe for fling on main thread, but there shouldn't be
any dependency to the call back function e.g. if you check scrollTop
in the callback function recursively and decide to finish the test based
on its value, the test will timeout because the callback function is never
called.

I changed the comment to make it more precise. 

[bokan, 2017/03/13 13:43:13]

Acknowledged.

   bool Swipe(gin::Arguments* args);
+
   bool ScrollBounce(gin::Arguments* args);
   bool PinchBy(gin::Arguments* args);
   bool Tap(gin::Arguments* args);
   bool PointerActionSequence(gin::Arguments* args);
   float VisualViewportX();
   float VisualViewportY();
   float VisualViewportHeight();
   float VisualViewportWidth();
   float PageScaleFactor();
   void ClearImageCache();
   int RunMicroBenchmark(gin::Arguments* args);
   bool SendMessageToMicroBenchmark(int id, v8::Local<v8::Object> message);
   bool HasGpuChannel();
   bool HasGpuProcess();
   void GetGpuDriverBugWorkarounds(gin::Arguments* args);
 
   DISALLOW_COPY_AND_ASSIGN(GpuBenchmarking);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_GPU_GPU_BENCHMARKING_EXTENSION_H_