Early terminate flings when scrolling impossible

content/child/touch_fling_gesture_curve_unittest.cc

   // Copyright 2014 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.
 
 // Tests for the TouchFlingGestureCurve.
 
 #include "content/child/touch_fling_gesture_curve.h"
 
 #include "base/memory/scoped_ptr.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/WebKit/public/platform/WebFloatPoint.h"
 #include "third_party/WebKit/public/platform/WebFloatSize.h"
 #include "third_party/WebKit/public/platform/WebGestureCurve.h"
 #include "third_party/WebKit/public/platform/WebGestureCurveTarget.h"
 #include "third_party/WebKit/public/platform/WebSize.h"
 
 using blink::WebFloatPoint;
 using blink::WebFloatSize;
 using blink::WebGestureCurve;
 using blink::WebGestureCurveTarget;
 using blink::WebSize;
 
 namespace {
 
 class MockGestureCurveTarget : public WebGestureCurveTarget {
  public:
-  virtual void scrollBy(const WebFloatSize& delta) {
+  virtual bool scrollBy(const WebFloatSize& delta,
+                        const WebFloatSize& velocity) OVERRIDE {
     cumulative_delta_.width += delta.width;
     cumulative_delta_.height += delta.height;
-  }
-
-  virtual void notifyCurrentFlingVelocity(const WebFloatSize& velocity) {
     current_velocity_ = velocity;
+    return true;
   }
 
   WebFloatSize cumulative_delta() const { return cumulative_delta_; }
   void resetCumulativeDelta() { cumulative_delta_ = WebFloatSize(); }
 
   WebFloatSize current_velocity() const { return current_velocity_; }
 
  private:
   WebFloatSize cumulative_delta_;
   WebFloatSize current_velocity_;
@@ skipping 18 matching lines @@
   EXPECT_EQ(target.current_velocity().height, 0);
   EXPECT_TRUE(curve->apply(0.45f, &target)); // Use non-uniform tick spacing.
   EXPECT_TRUE(curve->apply(1, &target));
   EXPECT_FALSE(curve->apply(1.5, &target));
   EXPECT_NEAR(target.cumulative_delta().width, 1193, 1);
   EXPECT_EQ(target.cumulative_delta().height, 0);
   EXPECT_EQ(target.current_velocity().width, 0);
   EXPECT_EQ(target.current_velocity().height, 0);
 }