Move overscroll bounce to impl thread

content/renderer/input/input_handler_proxy.cc

 // Copyright 2013 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/input/input_handler_proxy.h"
 
 #include "base/auto_reset.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "content/common/input/did_overscroll_params.h"
 #include "content/common/input/web_input_event_traits.h"
 #include "content/public/common/content_switches.h"
 #include "content/renderer/input/input_handler_proxy_client.h"
+#include "content/renderer/input/input_scroll_elasticity_controller.h"
 #include "third_party/WebKit/public/platform/Platform.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "ui/events/latency_info.h"
 #include "ui/gfx/frame_time.h"
 #include "ui/gfx/geometry/point_conversions.h"
 
 using blink::WebFloatPoint;
 using blink::WebFloatSize;
 using blink::WebGestureEvent;
 using blink::WebInputEvent;
@@ skipping 128 matching lines @@
       gesture_scroll_on_impl_thread_(false),
       gesture_pinch_on_impl_thread_(false),
       fling_may_be_active_on_main_thread_(false),
       disallow_horizontal_fling_scroll_(false),
       disallow_vertical_fling_scroll_(false),
       has_fling_animation_started_(false) {
   DCHECK(client);
   input_handler_->BindToClient(this);
   smooth_scroll_enabled_ = CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kEnableSmoothScrolling);
+
+#if defined(OS_MACOSX)
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableThreadedEventHandlingMac)) {
+    cc::ScrollElasticityControllerClient* scroll_elasticity_client =
+        input_handler->GetScrollElasticityControllerClient();
+    scroll_elasticity_controller_.reset(new InputScrollElasticityController(
+        scroll_elasticity_client));
+    scroll_elasticity_client->BindToController(
+        scroll_elasticity_controller_.get());
+  }
+#endif
 }
 
 InputHandlerProxy::~InputHandlerProxy() {}
 
 void InputHandlerProxy::WillShutdown() {
   input_handler_ = NULL;
   client_->WillShutdown();
 }
 
 InputHandlerProxy::EventDisposition
@@ skipping 637 matching lines @@
   // trigger a scroll, e.g., with a trivial time delta between fling updates.
   // Return true in this case to prevent early fling termination.
   if (std::abs(clipped_increment.width) < kScrollEpsilon &&
       std::abs(clipped_increment.height) < kScrollEpsilon)
     return true;
 
   return did_scroll;
 }
 
 }  // namespace content