cc: Use maximum tiling contents scales for picture layer scale

cc/layer_impl.cc

 // Copyright 2011 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/layer_impl.h"
 
 #include "base/debug/trace_event.h"
 #include "base/stringprintf.h"
 #include "base/values.h"
 #include "cc/animation_registrar.h"
@@ skipping 683 matching lines @@
 void LayerImpl::setContentsScale(float contentsScaleX, float contentsScaleY)
 {
     if (this->contentsScaleX() == contentsScaleX && this->contentsScaleY() == contentsScaleY)
         return;
 
     m_drawProperties.contents_scale_x = contentsScaleX;
     m_drawProperties.contents_scale_y = contentsScaleY;
     noteLayerPropertyChanged();
 }
 
+void LayerImpl::calculateContentsScale(
+    float idealContentsScale,
+    float* contentsScaleX,
+    float* contentsScaleY,
+    gfx::Size* contentBounds)
+{
+    // Base LayerImpl has all of its content scales and content bounds pushed
+    // from its Layer during commit and just reuses those values as-is.
+    *contentsScaleX = this->contentsScaleX();
+    *contentsScaleY = this->contentsScaleY();
+    *contentBounds = this->contentBounds();
+}
+
 void LayerImpl::setScrollOffset(gfx::Vector2d scrollOffset)
 {
     if (m_scrollOffset == scrollOffset)
         return;
 
     m_scrollOffset = scrollOffset;
     noteLayerPropertyChangedForSubtree();
 }
 
 void LayerImpl::setScrollDelta(const gfx::Vector2dF& scrollDelta)
@@ skipping 108 matching lines @@
         if (m_layerTreeImpl->settings().useLinearFadeScrollbarAnimator)
             m_scrollbarAnimationController = createScrollbarAnimationControllerWithFade(this);
         else
             m_scrollbarAnimationController = ScrollbarAnimationController::create(this);
     }
     m_scrollbarAnimationController->setVerticalScrollbarLayer(scrollbarLayer);
     m_scrollbarAnimationController->updateScrollOffset(this);
 }
 
 }  // namespace cc