Chromium compositor change implementing page-scale driven pinch-zoom.

cc/CCLayerImpl.cpp

 // 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 "config.h"
 
 #if USE(ACCELERATED_COMPOSITING)
 
 #include "CCLayerImpl.h"
 
@@ skipping 29 matching lines @@
     , m_opaque(false)
     , m_opacity(1.0)
     , m_preserves3D(false)
     , m_useParentBackfaceVisibility(false)
     , m_drawCheckerboardForMissingTiles(false)
     , m_useLCDText(false)
     , m_drawsContent(false)
     , m_forceRenderSurface(false)
     , m_isContainerForFixedPositionLayers(false)
     , m_fixedToContainerLayer(false)
-    , m_pageScaleDelta(1)
     , m_renderTarget(0)
     , m_drawDepth(0)
     , m_drawOpacity(0)
     , m_drawOpacityIsAnimating(false)
     , m_debugBorderColor(0)
     , m_debugBorderWidth(0)
     , m_drawTransformIsAnimating(false)
     , m_screenSpaceTransformIsAnimating(false)
 #ifndef NDEBUG
     , m_betweenWillDrawAndDidDraw(false)
@@ skipping 106 matching lines @@
 {
     return CCRenderPass::Id(0, 0);
 }
 
 CCResourceProvider::ResourceId CCLayerImpl::contentsResourceId() const
 {
     ASSERT_NOT_REACHED();
     return 0;
 }
 
-void CCLayerImpl::scrollBy(const FloatSize& scroll)
+FloatSize CCLayerImpl::scrollBy(const FloatSize& scroll)
 {
     IntSize minDelta = -toSize(m_scrollPosition);
     IntSize maxDelta = m_maxScrollPosition - toSize(m_scrollPosition);
     // Clamp newDelta so that position + delta stays within scroll bounds.
     FloatSize newDelta = (m_scrollDelta + scroll).expandedTo(minDelta).shrunkTo(maxDelta);
+    FloatSize unscrolled = m_scrollDelta + scroll - newDelta;
 
     if (m_scrollDelta == newDelta)
-        return;
+        return unscrolled;
 
     m_scrollDelta = newDelta;
     if (m_scrollbarAnimationController)
         m_scrollbarAnimationController->updateScrollOffset(this);
     noteLayerPropertyChangedForSubtree();
+
+    return unscrolled;
 }
 
 CCInputHandlerClient::ScrollStatus CCLayerImpl::tryScroll(const IntPoint& viewportPoint, CCInputHandlerClient::ScrollInputType type) const
 {
     if (shouldScrollOnMainThread()) {
         TRACE_EVENT0("cc", "CCLayerImpl::tryScroll: Failed shouldScrollOnMainThread");
         return CCInputHandlerClient::ScrollOnMainThread;
     }
 
     if (!screenSpaceTransform().isInvertible()) {
@@ skipping 399 matching lines @@
 
 void CCLayerImpl::setScrollDelta(const FloatSize& scrollDelta)
 {
     if (m_scrollDelta == scrollDelta)
         return;
 
     m_scrollDelta = scrollDelta;
     noteLayerPropertyChangedForSubtree();
 }
 
-void CCLayerImpl::setPageScaleDelta(float pageScaleDelta)
+void CCLayerImpl::setImplTransform(const WebKit::WebTransformationMatrix& transform)
 {
-    if (m_pageScaleDelta == pageScaleDelta)
+    if (m_implTransform == transform)
         return;
 
-    m_pageScaleDelta = pageScaleDelta;
+    m_implTransform = transform;
     noteLayerPropertyChangedForSubtree();
 }
 
 void CCLayerImpl::setDoubleSided(bool doubleSided)
 {
     if (m_doubleSided == doubleSided)
         return;
 
     m_doubleSided = doubleSided;
     noteLayerPropertyChangedForSubtree();
@@ skipping 42 matching lines @@
     if (!m_scrollbarAnimationController)
         m_scrollbarAnimationController = CCScrollbarAnimationController::create(this);
     m_scrollbarAnimationController->setVerticalScrollbarLayer(scrollbarLayer);
     m_scrollbarAnimationController->updateScrollOffset(this);
 }
 
 }
 
 
 #endif // USE(ACCELERATED_COMPOSITING)