Fix JS interface for synthetic smooth scroll.

content/renderer/gpu/gpu_benchmarking_extension.cc

Index: content/renderer/gpu/gpu_benchmarking_extension.cc
diff --git a/content/renderer/gpu/gpu_benchmarking_extension.cc b/content/renderer/gpu/gpu_benchmarking_extension.cc
index e3048157dce06875268d53bdca5357d1c74fc499..a5165222d818af64b0c28402f6d2ebebd91de6ff 100644
--- a/content/renderer/gpu/gpu_benchmarking_extension.cc
+++ b/content/renderer/gpu/gpu_benchmarking_extension.cc
@@ -283,11 +283,11 @@ class GpuBenchmarkingWrapper : public v8::Extension {
           "      chrome.gpuBenchmarking.DEFAULT_INPUT;"
           "  speed_in_pixels_s = opt_speed_in_pixels_s || 800;"
           "  native function BeginSmoothScroll();"
-          "  if (typeof opt_mouse_event_x !== 'undefined' &&"
-          "      typeof opt_mouse_event_y !== 'undefined') {"
+          "  if (typeof opt_start_x !== 'undefined' &&"
+          "      typeof opt_start_y !== 'undefined') {"
           "    return BeginSmoothScroll(pixels_to_scroll, callback,"
           "                             gesture_source_type, speed_in_pixels_s,"
-          "                             opt_mouse_event_x, opt_mouse_event_y);"
+          "                             opt_start_x, opt_start_y);"
           "  } else {"
           "    return BeginSmoothScroll(pixels_to_scroll, callback,"
           "                             gesture_source_type,"
@@ -477,7 +477,7 @@ class GpuBenchmarkingWrapper : public v8::Extension {
     if (!context.Init(false))
       return;
 
-    // Account for the 2 optional arguments, mouse_event_x and mouse_event_y.
+    // Account for the 2 optional arguments, start_x and start_y.
     int arglen = args.Length();
     if (arglen < 4 ||
         !args[0]->IsNumber() ||