Implement desktop compatibility viewport

cc/layer_tree_host_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_tree_host_impl.h"
 
 #include <algorithm>
 
 #include "base/basictypes.h"
 #include "base/debug/trace_event.h"
@@ skipping 789 matching lines @@
     m_fpsCounter->saveTimeStamp(base::TimeTicks::Now());
 
     if (m_debugState.showHudRects())
         m_debugRectHistory->saveDebugRectsForCurrentFrame(rootLayer(), *frame.renderSurfaceLayerList, frame.occludingScreenSpaceRects, frame.nonOccludingScreenSpaceRects, m_debugState);
 
     // Because the contents of the HUD depend on everything else in the frame, the contents
     // of its texture are updated as the last thing before the frame is drawn.
     if (m_activeTree->hud_layer())
         m_activeTree->hud_layer()->updateHudTexture(m_resourceProvider.get());
 
+    m_activeTree->UpdateFixedPositionViewport();
+
     m_renderer->drawFrame(frame.renderPasses);
     // The render passes should be consumed by the renderer.
     DCHECK(frame.renderPasses.empty());
     frame.renderPassesById.clear();
 
     // The next frame should start by assuming nothing has changed, and changes are noted as they occur.
     for (unsigned int i = 0; i < frame.renderSurfaceLayerList->size(); i++)
         (*frame.renderSurfaceLayerList)[i]->renderSurface()->damageTracker()->didDrawDamagedArea();
     rootLayer()->resetAllChangeTrackingForSubtree();
 }
@@ skipping 655 matching lines @@
         if (m_pinchGestureActive)
             computePinchZoomDeltas(scrollInfo.get());
         else if (m_pageScaleAnimation.get())
             computeDoubleTapZoomDeltas(scrollInfo.get());
         return scrollInfo.Pass();
     }
 
     collectScrollDeltas(scrollInfo.get(), rootLayer());
     scrollInfo->pageScaleDelta = m_pinchZoomViewport.page_scale_delta();
     m_pinchZoomViewport.set_sent_page_scale_delta(scrollInfo->pageScaleDelta);
+    if (rootScrollLayer()) {
+        scrollInfo->desktopCompatibilityViewportOffsetFromScrollPositionDelta = gfx::ToFlooredVector2d(rootScrollLayer()->desktopCompatibilityViewportOffsetFromScrollPositionDelta());
+        rootScrollLayer()->setSentDesktopCompatibilityViewportOffsetFromScrollPositionDelta(scrollInfo->desktopCompatibilityViewportOffsetFromScrollPositionDelta);
+    }
 
     return scrollInfo.Pass();
 }
 
 gfx::Transform LayerTreeHostImpl::implTransform() const
 {
     return m_pinchZoomViewport.ImplTransform(m_settings.pageScalePinchZoomEnabled);
 }
 
 void LayerTreeHostImpl::setFullRootLayerDamage()
@@ skipping 207 matching lines @@
     LayerImpl* layer = getNonCompositedContentLayerRecursive(tree->RootLayer());
     return layer ? layer->getPicture() : skia::RefPtr<SkPicture>();
 }
 
 void LayerTreeHostImpl::savePaintTime(const base::TimeDelta& totalPaintTime)
 {
     m_paintTimeCounter->SavePaintTime(totalPaintTime);
 }
 
 }  // namespace cc