Expose a benchmark-only beginSmoothScroll API to JS.

Credit for this goes to Cem Kocagil, who did key prototyping in
http://codereview.chromium.org/10164021/

BUG=120829


Review URL: https://chromiumcodereview.appspot.com/10443050

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@146657 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 40 insertions, 0 deletions

diff --git a/content/port/browser/render_widget_host_view_port.h b/content/port/browser/render_widget_host_view_port.h
index adc2f35..2c31ac0 100644
--- a/content/port/browser/render_widget_host_view_port.h
+++ b/content/port/browser/render_widget_host_view_port.h
@@ -40,6 +40,8 @@ struct WebScreenInfo;
 
 namespace content {
 
+class SmoothScrollGesture;
+
 // This is the larger RenderWidgetHostView interface exposed only
 // within content/ and to embedders looking to port to new platforms.
 // RenderWidgetHostView class hierarchy described in render_widget_host_view.h.
@@ -248,6 +250,11 @@ class CONTENT_EXPORT RenderWidgetHostViewPort : public RenderWidgetHostView {
   virtual void ProcessTouchAck(WebKit::WebInputEvent::Type type,
                                bool processed) = 0;
 
+  // Asks the view to create a smooth scroll gesture that will be used to
+  // simulate a user-initiated scroll.
+  virtual SmoothScrollGesture* CreateSmoothScrollGesture(
+      bool scroll_down, bool scroll_far) = 0;
+
   virtual void SetHasHorizontalScrollbar(bool has_horizontal_scrollbar) = 0;
   virtual void SetScrollOffsetPinning(
       bool is_pinned_to_left, bool is_pinned_to_right) = 0;
diff --git a/content/port/browser/smooth_scroll_gesture.h b/content/port/browser/smooth_scroll_gesture.h
new file mode 100644
index 0000000..6d6672c
--- /dev/null
+++ b/content/port/browser/smooth_scroll_gesture.h
@@ -0,0 +1,33 @@
+// 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_PORT_BROWSER_SMOOTH_SCROLL_GESTURE_H_
+#define CONTENT_PORT_BROWSER_SMOOTH_SCROLL_GESTURE_H_
+
+#include "base/time.h"
+
+namespace content {
+
+class RenderWidgetHost;
+
+// This is a base class representing a single scroll gesture. These gestures are
+// paired with the rendering benchmarking system to (automatically) measure how
+// smoothnly chrome is responding to user input.
+class SmoothScrollGesture {
+ public:
+  virtual ~SmoothScrollGesture() {}
+
+  // When called, the gesture should compute its state at the provided timestamp
+  // and send the right input events to the provided RenderWidgetHost to
+  // simulate the gesture having run up to that point in time.
+  //
+  // This function should return true until the gesture is over. A false return
+  // value will stop ticking the gesture and clean it up.
+  virtual bool ForwardInputEvents(base::TimeTicks now,
+                                  RenderWidgetHost* host) = 0;
+};
+
+} // namespace content
+
+#endif // CONTENT_PORT_BROWSER_SMOOTH_SCROLL_GESTURE_H_