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

cc/layer_tree_host.cc

Index: cc/layer_tree_host.cc
diff --git a/cc/layer_tree_host.cc b/cc/layer_tree_host.cc
index 7f37e23cf88f20d46572ce9737202d3b2b74e544..d7624b97fb2294ec303dca101f2d320e1d340a71 100644
--- a/cc/layer_tree_host.cc
+++ b/cc/layer_tree_host.cc
@@ -23,7 +23,11 @@
 #include "cc/math_util.h"
 #include "cc/occlusion_tracker.h"
 #include "cc/overdraw_metrics.h"
+#include "cc/pinch_zoom_scrollbar.h"
+#include "cc/pinch_zoom_scrollbar_geometry.h"
+#include "cc/pinch_zoom_scrollbar_painter.h"
 #include "cc/prioritized_resource_manager.h"
+#include "cc/scrollbar_layer.h"
 #include "cc/single_thread_proxy.h"
 #include "cc/switches.h"
 #include "cc/thread.h"
@@ -326,6 +330,11 @@ void LayerTreeHost::finishCommitOnImplThread(LayerTreeHostImpl* hostImpl)
             syncTree->ResetContentsTexturesPurged();
     }
 
+    syncTree->SetPinchZoomHorizontalLayerId(
+        m_pinchZoomScrollbarHorizontal ? m_pinchZoomScrollbarHorizontal->id() : -1);
+    syncTree->SetPinchZoomVerticalLayerId(
+        m_pinchZoomScrollbarVertical ? m_pinchZoomScrollbarVertical->id() : -1);
+
     if (!m_settings.implSidePainting) {
         // If we're not in impl-side painting, the tree is immediately
         // considered active.
@@ -338,6 +347,64 @@ void LayerTreeHost::finishCommitOnImplThread(LayerTreeHostImpl* hostImpl)
     m_commitNumber++;
 }
 
+void LayerTreeHost::setPinchZoomScrollbarsBoundsAndPosition()
+{
+    if (!m_pinchZoomScrollbarHorizontal || !m_pinchZoomScrollbarVertical)
+        return;
+
+    gfx::Size size = layoutViewportSize();
+    int trackWidth = PinchZoomScrollbarGeometry::kTrackWidth;
+
+    m_pinchZoomScrollbarHorizontal->setBounds(gfx::Size(size.width() - trackWidth, trackWidth));
+    m_pinchZoomScrollbarHorizontal->setPosition(gfx::PointF(0, size.height() - trackWidth));
+    m_pinchZoomScrollbarHorizontal->setNeedsDisplay();

[enne (OOO), 2013/03/06 19:32:58]

setBounds should take care of this if anything changes.

[wjmaclean, 2013/03/06 22:36:53]

Removed.

+
+    m_pinchZoomScrollbarVertical->setBounds(gfx::Size(trackWidth, size.height() - trackWidth));
+    m_pinchZoomScrollbarVertical->setPosition(gfx::PointF(size.width() - trackWidth, 0));
+    m_pinchZoomScrollbarVertical->setNeedsDisplay();
+}
+
+static scoped_refptr<ScrollbarLayer> CreatePinchZoomScrollbar(
+    WebKit::WebScrollbar::Orientation orientation, LayerTreeHost* owner)
+{
+    scoped_refptr<ScrollbarLayer> scrollbarLayer = ScrollbarLayer::create(
+        make_scoped_ptr(
+            new PinchZoomScrollbar(orientation, owner)).PassAs<WebKit::WebScrollbar>(),
+        scoped_ptr<ScrollbarThemePainter>(new PinchZoomScrollbarPainter).Pass(),
+        scoped_ptr<WebKit::WebScrollbarThemeGeometry>(
+            new PinchZoomScrollbarGeometry).Pass(),
+        -1);
+        scrollbarLayer->setIsDrawable(true);
+        scrollbarLayer->setOpacity(0);
+        return scrollbarLayer;
+}
+
+void LayerTreeHost::createAndAddPinchZoomScrollbars()
+{
+    bool needsPropertiesUpdated = false;
+
+    if (!m_pinchZoomScrollbarHorizontal) {

[enne (OOO), 2013/03/06 19:32:58]

It's always the case that you have both pinch zoom scrollbars or neither, right?
Just asking, since this way these conditionals are structured it looks like it
could be the case that you could enter into this function having only one or the
other.

[wjmaclean, 2013/03/06 22:36:53]

If nothing is wrong, then yes, we have both or neither. I guess I was just
programming for the worst case here, but have changed the condition to re-create
both if either is missing. That way it's always clear we expect to have both.

+        m_pinchZoomScrollbarHorizontal = CreatePinchZoomScrollbar(WebKit::WebScrollbar::Horizontal, this);
+        needsPropertiesUpdated = true;
+    }
+
+    if (!m_pinchZoomScrollbarVertical) {
+        m_pinchZoomScrollbarVertical = CreatePinchZoomScrollbar( WebKit::WebScrollbar::Vertical, this);
+        needsPropertiesUpdated = true;
+    }
+
+    DCHECK(m_pinchZoomScrollbarHorizontal && m_pinchZoomScrollbarVertical);
+
+    if (!m_pinchZoomScrollbarHorizontal->parent())
+        m_rootLayer->addChild(m_pinchZoomScrollbarHorizontal);
+
+    if (!m_pinchZoomScrollbarVertical->parent())
+        m_rootLayer->addChild(m_pinchZoomScrollbarVertical);
+
+    if (needsPropertiesUpdated)
+        setPinchZoomScrollbarsBoundsAndPosition();
+}
+
 void LayerTreeHost::willCommit()
 {
     m_client->willCommit();
@@ -355,6 +422,10 @@ void LayerTreeHost::updateHudLayer()
         m_hudLayer->removeFromParent();
         m_hudLayer = 0;
     }
+
+    // Setup pinch-zoom scrollbars if required.

[enne (OOO), 2013/03/06 19:32:58]

This comment doesn't really add anything.

[wjmaclean, 2013/03/06 22:36:53]

Done.

It used to mean more before the last re-factor I guess.

+    if (m_settings.usePinchZoomScrollbars)
+        createAndAddPinchZoomScrollbars();
 }
 
 void LayerTreeHost::commitComplete()
@@ -501,6 +572,7 @@ void LayerTreeHost::setViewportSize(const gfx::Size& layoutViewportSize, const g
     m_layoutViewportSize = layoutViewportSize;
     m_deviceViewportSize = deviceViewportSize;
 
+    setPinchZoomScrollbarsBoundsAndPosition();
     setNeedsCommit();
 }
 
@@ -594,6 +666,11 @@ static Layer* findFirstScrollableLayer(Layer* layer)
     return 0;
 }
 
+Layer* LayerTreeHost::rootScrollLayer() const
+{
+    return findFirstScrollableLayer(m_rootLayer.get());
+}
+
 void LayerTreeHost::updateLayers(Layer* rootLayer, ResourceUpdateQueue& queue)
 {
     TRACE_EVENT0("cc", "LayerTreeHost::updateLayers");
@@ -887,10 +964,21 @@ void LayerTreeHost::setAnimationEventsRecursive(const AnimationEventsVector& eve
 
     for (size_t eventIndex = 0; eventIndex < events.size(); ++eventIndex) {
         if (layer->id() == events[eventIndex].layerId) {
-            if (events[eventIndex].type == AnimationEvent::Started)
+            switch (events[eventIndex].type) {
+            case AnimationEvent::Started :
                 layer->notifyAnimationStarted(events[eventIndex], wallClockTime.ToDoubleT());
-            else
+                break;
+            case AnimationEvent::Finished :
                 layer->notifyAnimationFinished(wallClockTime.ToDoubleT());
+                break;
+
+            case AnimationEvent::PropertyUpdate :
+                layer->notifyAnimationPropertyUpdate(events[eventIndex]);
+                break;
+
+            default:
+                NOTREACHED();
+            }
         }
     }