Add a completion callback to gpuBenchmarking.beginSmoothScroll

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 6f4fccc4bf99f77475c63c588a7392a0493e6801..2e0f1aed7064486d94fcb5ecfd0d5dd24375abc1 100644
--- a/content/renderer/gpu/gpu_benchmarking_extension.cc
+++ b/content/renderer/gpu/gpu_benchmarking_extension.cc
@@ -135,15 +135,18 @@ class GpuBenchmarkingWrapper : public v8::Extension {
           "  return PrintToSkPicture(dirname);"
           "};"
           "chrome.gpuBenchmarking.beginSmoothScrollDown = "
-          "    function(scroll_far) {"
+          "    function(scroll_far, opt_callback) {"
           "  scroll_far = scroll_far || false;"
+          "  callback = opt_callback || function() { };"
           "  native function BeginSmoothScroll();"
-          "  return BeginSmoothScroll(true, scroll_far);"
+          "  return BeginSmoothScroll(true, scroll_far, callback);"
           "};"
-          "chrome.gpuBenchmarking.beginSmoothScrollUp = function(scroll_far) {"
+          "chrome.gpuBenchmarking.beginSmoothScrollUp = "
+          "    function(scroll_far, opt_callback) {"
           "  scroll_far = scroll_far || false;"
+          "  callback = opt_callback || function() { };"
           "  native function BeginSmoothScroll();"
-          "  return BeginSmoothScroll(false, scroll_far);"
+          "  return BeginSmoothScroll(false, scroll_far, callback);"
           "};"
           "chrome.gpuBenchmarking.runRenderingBenchmarks = function(filter) {"
           "  native function RunRenderingBenchmarks();"
@@ -230,6 +233,21 @@ class GpuBenchmarkingWrapper : public v8::Extension {
     return v8::Undefined();
   }
 
+  static void OnSmoothScrollCompleted(v8::Persistent<v8::Function> callback,
+                                      v8::Persistent<v8::Context> context) {
+    v8::HandleScope scope;
+    v8::Context::Scope context_scope(context);
+    WebFrame* frame = WebFrame::frameForContext(context);
+    if (frame) {
+      frame->callFunctionEvenIfScriptDisabled(callback,
+                                              v8::Object::New(),
+                                              0,
+                                              NULL);
+    }
+    callback.Dispose();
+    context.Dispose();
+  }
+
   static v8::Handle<v8::Value> BeginSmoothScroll(const v8::Arguments& args) {
     WebFrame* web_frame = WebFrame::frameForEnteredContext();
     if (!web_frame)
@@ -243,13 +261,31 @@ class GpuBenchmarkingWrapper : public v8::Extension {
     if (!render_view_impl)
       return v8::Undefined();
 
-    if (args.Length() != 2 || !args[0]->IsBoolean() || !args[1]->IsBoolean())
+    if (args.Length() != 3 ||
+        !args[0]->IsBoolean() ||
+        !args[1]->IsBoolean() ||
+        !args[2]->IsFunction())
       return v8::False();
 
     bool scroll_down = args[0]->BooleanValue();
     bool scroll_far = args[1]->BooleanValue();
+    v8::Local<v8::Function> callback_local =
+        v8::Local<v8::Function>(v8::Function::Cast(*args[2]));
+    v8::Persistent<v8::Function> callback =
+        v8::Persistent<v8::Function>::New(callback_local);
+    v8::Persistent<v8::Context> context =
+        v8::Persistent<v8::Context>::New(web_frame->mainWorldScriptContext());
+
+    // TODO(nduca): If the render_view_impl is destroyed while the gesture is in
+    // progress, we will leak the callback and context. This needs to be fixed,
+    // somehow.
+    render_view_impl->BeginSmoothScroll(
+        scroll_down,
+        scroll_far,
+        base::Bind(&OnSmoothScrollCompleted,
+                   callback,
+                   context));
 
-    render_view_impl->BeginSmoothScroll(scroll_down, scroll_far);
     return v8::True();
   }