Add smoothness test for hover during trackpad scrolling [perf implications]

content/renderer/gpu/gpu_benchmarking_extension.cc

 // 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.
 
 #include "content/renderer/gpu/gpu_benchmarking_extension.h"
 
 #include <string>
 
 #include "base/base64.h"
 #include "base/files/file_path.h"
@@ skipping 271 matching lines @@
                        int gesture_source_type,
                        const std::string& direction,
                        float speed_in_pixels_s,
                        bool prevent_fling,
                        float start_x,
                        float start_y) {
   GpuBenchmarkingContext context;
   if (!context.Init(false))
     return false;
 
+  // Convert coordinates from CSS pixels to density independent pixels (DIPs).
+  float page_scale_factor = context.web_view()->pageScaleFactor();
+
+  if (gesture_source_type == SyntheticGestureParams::MOUSE_INPUT) {
+    // Ensure the mouse is centered and visible, in case it will
+    // trigger any hover or mousemove effects.
+    blink::WebRect contentRect =
+        context.web_view()->mainFrame()->visibleContentRect();
+    blink::WebMouseEvent mouseMove;
+    mouseMove.type = blink::WebInputEvent::MouseMove;
+    mouseMove.x = (contentRect.x + contentRect.width / 2) * page_scale_factor;
+    mouseMove.y = (contentRect.y + contentRect.height / 2) * page_scale_factor;
+    context.web_view()->handleInputEvent(mouseMove);
+    context.web_view()->setCursorVisibilityState(true);
+  }
+
   scoped_refptr<CallbackAndContext> callback_and_context =
       new CallbackAndContext(
           isolate, callback, context.web_frame()->mainWorldScriptContext());
 
   scoped_ptr<SyntheticSmoothScrollGestureParams> gesture_params(
       new SyntheticSmoothScrollGestureParams);
 
-  // Convert coordinates from CSS pixels to density independent pixels (DIPs).
-  float page_scale_factor = context.web_view()->pageScaleFactor();
-
   if (gesture_source_type < 0 ||
       gesture_source_type > SyntheticGestureParams::GESTURE_SOURCE_TYPE_MAX) {
     return false;
   }
   gesture_params->gesture_source_type =
       static_cast<SyntheticGestureParams::GestureSourceType>(
           gesture_source_type);
 
   gesture_params->speed_in_pixels_s = speed_in_pixels_s;
   gesture_params->prevent_fling = prevent_fling;
@@ skipping 522 matching lines @@
 
   return context.compositor()->SendMessageToMicroBenchmark(id, value.Pass());
 }
 
 bool GpuBenchmarking::HasGpuProcess() {
     GpuChannelHost* gpu_channel = RenderThreadImpl::current()->GetGpuChannel();
     return !!gpu_channel;
 }
 
 }  // namespace content