Implement pinch-zoom scaling for main-frame scrollbars and pinch-zoom overlay scrollbars.

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 426 matching lines @@
     }
 }
 
 bool LayerTreeHostImpl::calculateRenderPasses(FrameData& frame)
 {
     DCHECK(frame.renderPasses.empty());
 
     if (!canDraw() || !rootLayer())
       return false;
 
+    // Set the opacity of the pinch zoom scrollbars. This is done here
+    // so that it comes after the commit and we can directly set the
+    // opacity on the impl scrollbar layers.
+    activeTree()->SetPinchZoomScrollbarsVisibility();

[jamesr, 2013/02/26 20:48:46]

Why is this different for the pinch zoom scrollbars vs any other type of
scrollbar that has opacity animations?

[wjmaclean, 2013/03/01 15:30:32]

Because I had thought in the initial CL we would do this simply, and not via
animations. I've added animations now, so this will be gone in the next patch.

The existing animator for scrollbars requires that the scrollbars be managed by
a layerImpl, which is not the case for PZ scrollbars.

The new patch animates the scrollbars using vollick@'s animation framework,
which I think should replace the current ScrollbarAnimationController eventually
(soon, even).

+
     trackDamageForAllSurfaces(rootLayer(), *frame.renderSurfaceLayerList);
 
     TRACE_EVENT1("cc", "LayerTreeHostImpl::calculateRenderPasses", "renderSurfaceLayerList.size()", static_cast<long long unsigned>(frame.renderSurfaceLayerList->size()));
 
     // Create the render passes in dependency order.
     for (int surfaceIndex = frame.renderSurfaceLayerList->size() - 1; surfaceIndex >= 0 ; --surfaceIndex) {
         LayerImpl* renderSurfaceLayer = (*frame.renderSurfaceLayerList)[surfaceIndex];
         renderSurfaceLayer->renderSurface()->appendRenderPasses(frame);
     }
 
@@ skipping 889 matching lines @@
         // Allow further movement only on an axis perpendicular to the direction in which the layer
         // moved.
         gfx::Vector2dF perpendicularAxis(-appliedDelta.y(), appliedDelta.x());
         pendingDelta = MathUtil::projectVector(pendingDelta, perpendicularAxis);
 
         if (gfx::ToFlooredVector2d(pendingDelta).IsZero())
             break;
     }
 
     if (didScroll) {
+        activeTree()->UpdatePinchZoomScrollbarsIfNeeded();
         m_client->setNeedsCommitOnImplThread();
         m_client->setNeedsRedrawOnImplThread();
         m_client->renewTreePriority();
     }
     return didScroll;
 }
 
 void LayerTreeHostImpl::clearCurrentlyScrollingLayer()
 {
     m_activeTree->ClearCurrentlyScrollingLayer();
     m_didLockScrollingLayer = false;
 }
 
 void LayerTreeHostImpl::scrollEnd()
 {
     if (m_topControlsManager)
         m_topControlsManager->ScrollEnd();
     clearCurrentlyScrollingLayer();
+    if (activeTree()->HasPinchZoomScrollbars())
+        m_client->setNeedsRedrawOnImplThread();
 }
 
 void LayerTreeHostImpl::pinchGestureBegin()
 {
     m_pinchGestureActive = true;
     m_previousPinchAnchor = gfx::Point();
     m_client->renewTreePriority();
 }
 
 void LayerTreeHostImpl::pinchGestureUpdate(float magnifyDelta, gfx::Point anchor)
@@ skipping 336 matching lines @@
         m_tileManager->SetRecordRenderingStats(m_debugState.recordRenderingStats());
 }
 
 void LayerTreeHostImpl::savePaintTime(const base::TimeDelta& totalPaintTime, int commitNumber)
 {
     DCHECK(m_debugState.continuousPainting);
     m_paintTimeCounter->SavePaintTime(totalPaintTime, commitNumber);
 }
 
 }  // namespace cc