Move page scale ownership to LayerTreeImpl.

cc/pinch_zoom_viewport.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/pinch_zoom_viewport.h"
-
-#include "base/logging.h"
-
-namespace cc {
-
-PinchZoomViewport::PinchZoomViewport()
-    : page_scale_factor_(1),
-      page_scale_delta_(1),
-      sent_page_scale_delta_(1),
-      min_page_scale_factor_(0),
-      max_page_scale_factor_(0),
-      device_scale_factor_(1) {
-}
-
-void PinchZoomViewport::set_page_scale_delta(float delta) {
-  // Clamp to the current min/max limits.
-  float totalPageScaleFactor = page_scale_factor_ * delta;
-  if (min_page_scale_factor_ && totalPageScaleFactor < min_page_scale_factor_)
-    delta = min_page_scale_factor_ / page_scale_factor_;
-  else if (max_page_scale_factor_ &&
-           totalPageScaleFactor > max_page_scale_factor_)
-    delta = max_page_scale_factor_ / page_scale_factor_;
-
-  if (delta == page_scale_delta_)
-    return;
-
-  page_scale_delta_ = delta;
-}
-
-bool PinchZoomViewport::SetPageScaleFactorAndLimits(
-    float page_scale_factor,
-    float min_page_scale_factor,
-    float max_page_scale_factor) {
-  DCHECK(page_scale_factor);
-
-  if (sent_page_scale_delta_ == 1 && page_scale_factor == page_scale_factor_ &&
-      min_page_scale_factor == min_page_scale_factor_ &&
-      max_page_scale_factor == max_page_scale_factor_)
-    return false;
-
-  min_page_scale_factor_ = min_page_scale_factor;
-  max_page_scale_factor_ = max_page_scale_factor;
-
-  page_scale_factor_ = page_scale_factor;
-  return true;
-}
-
-gfx::Transform PinchZoomViewport::ImplTransform(
-    bool page_scale_pinch_zoom_enabled) const {
-  gfx::Transform transform;
-  transform.Scale(page_scale_delta_, page_scale_delta_);
-
-  if (page_scale_pinch_zoom_enabled)
-    transform.Scale(page_scale_factor_, page_scale_factor_);
-
-  return transform;
-}
-
-}  // namespace cc