Pass accurate contentsScale to LayerImpl.

cc/scrollbar_layer_impl.cc

 // Copyright 2012 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 "config.h"
 
 #include "cc/scrollbar_layer_impl.h"
 
 #include "cc/quad_sink.h"
 #include "cc/scrollbar_animation_controller.h"
@@ skipping 54 matching lines @@
 
     m_geometry->update(scrollbar);
 }
 
 static FloatRect toUVRect(const WebRect& r, const IntRect& bounds)
 {
     return FloatRect(static_cast<float>(r.x) / bounds.width(), static_cast<float>(r.y) / bounds.height(),
                      static_cast<float>(r.width) / bounds.width(), static_cast<float>(r.height) / bounds.height());
 }
 
+IntRect ScrollbarLayerImpl::scrollbarLayerRectToContentRect(const WebRect& layerRect) const
+{
+    // Don't intersect with the bounds as in layerRectToContentRect() because
+    // layerRect here might be in coordinates of the containing layer.
+    FloatRect contentRect(layerRect.x, layerRect.y, layerRect.width, layerRect.height);
+    contentRect.scale(contentsScaleX(), contentsScaleY());
+    return enclosingIntRect(contentRect);
+}
+
 void ScrollbarLayerImpl::appendQuads(QuadSink& quadSink, AppendQuadsData& appendQuadsData)
 {
     bool premultipledAlpha = false;
     bool flipped = false;
     FloatRect uvRect(0, 0, 1, 1);
     IntRect boundsRect(IntPoint(), bounds());
     IntRect contentBoundsRect(IntPoint(), contentBounds());
 
     SharedQuadState* sharedQuadState = quadSink.useSharedQuadState(createSharedQuadState());
     appendDebugBorderQuad(quadSink, sharedQuadState, appendQuadsData);
 
     WebRect thumbRect, backTrackRect, foreTrackRect;
     m_geometry->splitTrack(&m_scrollbar, m_geometry->trackRect(&m_scrollbar), backTrackRect, thumbRect, foreTrackRect);
     if (!m_geometry->hasThumb(&m_scrollbar))
         thumbRect = WebRect();
 
     if (m_thumbResourceId && !thumbRect.isEmpty()) {
-        scoped_ptr<TextureDrawQuad> quad = TextureDrawQuad::create(sharedQuadState, layerRectToContentRect(thumbRect), m_thumbResourceId, premultipledAlpha, uvRect, flipped);
+        scoped_ptr<TextureDrawQuad> quad = TextureDrawQuad::create(sharedQuadState, scrollbarLayerRectToContentRect(thumbRect), m_thumbResourceId, premultipledAlpha, uvRect, flipped);
         quad->setNeedsBlending();
         quadSink.append(quad.PassAs<DrawQuad>(), appendQuadsData);
     }
 
     if (!m_backTrackResourceId)
         return;
 
     // We only paint the track in two parts if we were given a texture for the forward track part.
     if (m_foreTrackResourceId && !foreTrackRect.isEmpty())
-        quadSink.append(TextureDrawQuad::create(sharedQuadState, layerRectToContentRect(foreTrackRect), m_foreTrackResourceId, premultipledAlpha, toUVRect(foreTrackRect, boundsRect), flipped).PassAs<DrawQuad>(), appendQuadsData);
+        quadSink.append(TextureDrawQuad::create(sharedQuadState, scrollbarLayerRectToContentRect(foreTrackRect), m_foreTrackResourceId, premultipledAlpha, toUVRect(foreTrackRect, boundsRect), flipped).PassAs<DrawQuad>(), appendQuadsData);
 
     // Order matters here: since the back track texture is being drawn to the entire contents rect, we must append it after the thumb and
     // fore track quads. The back track texture contains (and displays) the buttons.
     if (!contentBoundsRect.isEmpty())
         quadSink.append(TextureDrawQuad::create(sharedQuadState, IntRect(contentBoundsRect), m_backTrackResourceId, premultipledAlpha, uvRect, flipped).PassAs<DrawQuad>(), appendQuadsData);
 }
 
 void ScrollbarLayerImpl::didLoseContext()
 {
     m_backTrackResourceId = 0;
@@ skipping 80 matching lines @@
 {
     return m_owner->m_isCustomScrollbar;
 }
 
 const char* ScrollbarLayerImpl::layerTypeAsString() const
 {
     return "ScrollbarLayer";
 }
 
 }