(Reland) Always create top controls manager

cc/input/top_controls_manager_unittest.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 "cc/input/top_controls_manager.h"
 
 #include <algorithm>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
@@ skipping 391 matching lines @@
 
   client.SetTopControlsHeight(50.f);
   EXPECT_FALSE(manager->animation());
   EXPECT_FLOAT_EQ(50.f, manager->TopControlsHeight());
   EXPECT_FLOAT_EQ(0.f, manager->ControlsTopOffset());
 }
 
 TEST(TopControlsManagerTest, GrowingHeightKeepsTopControlsHidden) {
   MockTopControlsManagerClient client(0.f, 0.5f, 0.5f);
   TopControlsManager* manager = client.manager();
+  client.SetTopControlsHeight(1.f);
   manager->UpdateTopControlsState(HIDDEN, HIDDEN, false);
-  EXPECT_EQ(0.f, manager->ControlsTopOffset());
+  EXPECT_EQ(-1.f, manager->ControlsTopOffset());
   EXPECT_EQ(0.f, manager->ContentTopOffset());
 
   client.SetTopControlsHeight(50.f);
   EXPECT_FALSE(manager->animation());
   EXPECT_EQ(-50.f, manager->ControlsTopOffset());
   EXPECT_EQ(0.f, manager->ContentTopOffset());
 
   client.SetTopControlsHeight(100.f);
   EXPECT_FALSE(manager->animation());
   EXPECT_EQ(-100.f, manager->ControlsTopOffset());
@@ skipping 14 matching lines @@
   EXPECT_FALSE(manager->animation());
   EXPECT_FLOAT_EQ(-50.f, manager->ControlsTopOffset());
   EXPECT_FLOAT_EQ(0.f, manager->ContentTopOffset());
 
   client.SetTopControlsHeight(0.f);
   EXPECT_FALSE(manager->animation());
   EXPECT_FLOAT_EQ(0.f, manager->ControlsTopOffset());
   EXPECT_FLOAT_EQ(0.f, manager->ContentTopOffset());
 }
 
+TEST(TopControlsManagerTest, ZeroTopControlsHeightDisablesManager) {
+  MockTopControlsManagerClient client(0.f, 0.5f, 0.5f);
+  client.SetCurrentTopControlsShownRatio(0.f);
+  TopControlsManager* manager = client.manager();
+
+  EXPECT_FLOAT_EQ(0.f, manager->ControlsTopOffset());
+  EXPECT_FLOAT_EQ(0.f, manager->ContentTopOffset());
+  EXPECT_FLOAT_EQ(0.f, manager->TopControlsShownRatio());
+  EXPECT_FLOAT_EQ(0.f, manager->TopControlsHeight());
+
+  manager->UpdateTopControlsState(SHOWN, SHOWN, true);
+  EXPECT_FALSE(manager->animation());
+  EXPECT_EQ(TopControlsManager::NO_ANIMATION, manager->animation_direction());
+  EXPECT_FLOAT_EQ(0.f, manager->TopControlsShownRatio());
+
+  manager->ScrollBegin();
+  EXPECT_FLOAT_EQ(10.f, manager->ScrollBy(gfx::Vector2dF(0.f, 10.f)).y());
+  manager->ScrollEnd();
+  EXPECT_FALSE(manager->animation());
+  EXPECT_EQ(TopControlsManager::NO_ANIMATION, manager->animation_direction());
+  EXPECT_FLOAT_EQ(0.f, manager->ControlsTopOffset());
+  EXPECT_FLOAT_EQ(0.f, manager->ContentTopOffset());
+  EXPECT_FLOAT_EQ(0.f, manager->TopControlsShownRatio());
+
+  manager->PinchBegin();
+  manager->PinchEnd();
+  EXPECT_FALSE(manager->animation());
+  EXPECT_EQ(TopControlsManager::NO_ANIMATION, manager->animation_direction());
+  EXPECT_FLOAT_EQ(0.f, manager->ControlsTopOffset());
+  EXPECT_FLOAT_EQ(0.f, manager->ContentTopOffset());
+  EXPECT_FLOAT_EQ(0.f, manager->TopControlsShownRatio());
+
+  manager->MainThreadHasStoppedFlinging();
+  EXPECT_FALSE(manager->animation());
+  EXPECT_EQ(TopControlsManager::NO_ANIMATION, manager->animation_direction());
+  EXPECT_FLOAT_EQ(0.f, manager->ControlsTopOffset());
+  EXPECT_FLOAT_EQ(0.f, manager->ContentTopOffset());
+  EXPECT_FLOAT_EQ(0.f, manager->TopControlsShownRatio());
+}
+
 }  // namespace
 }  // namespace cc