Bug 1105109 - Have the parent process notify APZ of the start and stop of autoscrolling. r=kats

The messages are routed through nsITabParent, nsIWidget, and IAPZCTreeManager
(the latter possibly remoted via PAPZCTreeManager if out-of-process compositing
is used).

MozReview-Commit-ID: 1zXzLa1fqpG

--HG--
extra : rebase_source : c482816ecbaec0a889d817851ee15be186b2a49c

dom/interfaces/base/nsITabParent.idl

@@ -7,6 +7,8 @@
 
 interface nsIPrincipal;
 
+typedef unsigned long long nsViewID;
+
 [builtinclass, scriptable, uuid(8e49f7b0-1f98-4939-bf91-e9c39cd56434)]
 interface nsITabParent : nsISupports
 {
@@ -75,4 +77,20 @@ interface nsITabParent : nsISupports
    * an onbeforeunload event handler.
    */
   readonly attribute boolean hasBeforeUnload;
+
+  /**
+   * Notify APZ to start autoscrolling.
+   * (aAnchorX, aAnchorY) are the coordinates of the autoscroll anchor,
+   * in LayoutDevice coordinates relative to the screen. aScrollId and 
+   * aPresShellId identify the scroll frame that content chose to scroll.
+   */
+  void startApzAutoscroll(in float aAnchorX, in float aAnchorY,
+                          in nsViewID aScrollId, in uint32_t aPresShellId);
+
+  /**
+   * Notify APZ to stop autoscrolling.
+   * aScrollId and aPresShellId identify the scroll frame that is being
+   * autoscrolled.
+   */
+  void stopApzAutoscroll(in nsViewID aScrollId, in uint32_t aPresShellId);
 };

dom/ipc/TabParent.cpp

@@ -3263,6 +3263,50 @@ TabParent::StartPersistence(uint64_t aOuterWindowID,
   // (The actor will be destroyed on constructor failure.)
 }
 
+NS_IMETHODIMP
+TabParent::StartApzAutoscroll(float aAnchorX, float aAnchorY,
+                              nsViewID aScrollId, uint32_t aPresShellId)
+{
+  if (!AsyncPanZoomEnabled()) {
+    return NS_OK;
+  }
+
+  if (RenderFrameParent* renderFrame = GetRenderFrame()) {
+    uint64_t layersId = renderFrame->GetLayersId();
+    if (nsCOMPtr<nsIWidget> widget = GetWidget()) {
+      ScrollableLayerGuid guid{layersId, aPresShellId, aScrollId};
+
+      // The anchor coordinates that are passed in are relative to the origin
+      // of the screen, but we are sending them to APZ which only knows about
+      // coordinates relative to the widget, so convert them accordingly.
+      LayoutDeviceIntPoint anchor = RoundedToInt(LayoutDevicePoint{aAnchorX, aAnchorY});
+      anchor -= widget->WidgetToScreenOffset();
+
+      widget->StartAsyncAutoscroll(
+          ViewAs<ScreenPixel>(anchor, PixelCastJustification::LayoutDeviceIsScreenForBounds),
+          guid);
+    }
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TabParent::StopApzAutoscroll(nsViewID aScrollId, uint32_t aPresShellId)
+{
+  if (!AsyncPanZoomEnabled()) {
+    return NS_OK;
+  }
+
+  if (RenderFrameParent* renderFrame = GetRenderFrame()) {
+    uint64_t layersId = renderFrame->GetLayersId();
+    if (nsCOMPtr<nsIWidget> widget = GetWidget()) {
+      ScrollableLayerGuid guid{layersId, aPresShellId, aScrollId};
+      widget->StopAsyncAutoscroll(guid);
+    }
+  }
+  return NS_OK;
+}
+
 ShowInfo
 TabParent::GetShowInfo()
 {

gfx/layers/apz/public/IAPZCTreeManager.h

@@ -183,6 +183,12 @@ public:
       const ScrollableLayerGuid& aGuid,
       const AsyncDragMetrics& aDragMetrics) = 0;
 
+  virtual void StartAutoscroll(
+      const ScrollableLayerGuid& aGuid,
+      const ScreenPoint& aAnchorLocation) = 0;
+
+  virtual void StopAutoscroll(const ScrollableLayerGuid& aGuid) = 0;
+
   /**
    * Function used to disable LongTap gestures.
    *

gfx/layers/apz/src/APZCTreeManager.cpp

@@ -669,6 +669,23 @@ APZCTreeManager::StartScrollbarDrag(const ScrollableLayerGuid& aGuid,
   mInputQueue->ConfirmDragBlock(inputBlockId, apzc, aDragMetrics);
 }
 
+void
+APZCTreeManager::StartAutoscroll(const ScrollableLayerGuid& aGuid,
+                                 const ScreenPoint& aAnchorLocation)
+{
+  if (RefPtr<AsyncPanZoomController> apzc = GetTargetAPZC(aGuid)) {
+    apzc->StartAutoscroll(aAnchorLocation);
+  }
+}
+
+void
+APZCTreeManager::StopAutoscroll(const ScrollableLayerGuid& aGuid)
+{
+  if (RefPtr<AsyncPanZoomController> apzc = GetTargetAPZC(aGuid)) {
+    apzc->StopAutoscroll();
+  }
+}
+
 void
 APZCTreeManager::NotifyScrollbarDragRejected(const ScrollableLayerGuid& aGuid) const
 {

gfx/layers/apz/src/APZCTreeManager.h

@@ -435,6 +435,11 @@ public:
       const ScrollableLayerGuid& aGuid,
       const AsyncDragMetrics& aDragMetrics) override;
 
+  void StartAutoscroll(const ScrollableLayerGuid& aGuid,
+                       const ScreenPoint& aAnchorLocation) override;
+
+  void StopAutoscroll(const ScrollableLayerGuid& aGuid) override;
+
   /*
    * Build the chain of APZCs that will handle overscroll for a pan starting at |aInitialTarget|.
    */

gfx/layers/ipc/APZCTreeManagerChild.cpp

@@ -207,6 +207,20 @@ APZCTreeManagerChild::StartScrollbarDrag(
   SendStartScrollbarDrag(aGuid, aDragMetrics);
 }
 
+void
+APZCTreeManagerChild::StartAutoscroll(
+    const ScrollableLayerGuid& aGuid,
+    const ScreenPoint& aAnchorLocation)
+{
+  SendStartAutoscroll(aGuid, aAnchorLocation);
+}
+
+void
+APZCTreeManagerChild::StopAutoscroll(const ScrollableLayerGuid& aGuid)
+{
+  SendStopAutoscroll(aGuid);
+}
+
 void
 APZCTreeManagerChild::SetLongTapEnabled(bool aTapGestureEnabled)
 {

gfx/layers/ipc/APZCTreeManagerChild.h

@@ -70,6 +70,14 @@ public:
           const ScrollableLayerGuid& aGuid,
           const AsyncDragMetrics& aDragMetrics) override;
 
+  void
+  StartAutoscroll(
+          const ScrollableLayerGuid& aGuid,
+          const ScreenPoint& aAnchorLocation) override;
+
+  void
+  StopAutoscroll(const ScrollableLayerGuid& aGuid) override;
+
   void
   SetLongTapEnabled(bool aTapGestureEnabled) override;
 

gfx/layers/ipc/APZCTreeManagerParent.cpp

@@ -300,6 +300,43 @@ APZCTreeManagerParent::RecvStartScrollbarDrag(
   return IPC_OK();
 }
 
+mozilla::ipc::IPCResult
+APZCTreeManagerParent::RecvStartAutoscroll(
+    const ScrollableLayerGuid& aGuid,
+    const ScreenPoint& aAnchorLocation)
+{
+  // Unlike RecvStartScrollbarDrag(), this message comes from the parent
+  // process (via nsBaseWidget::mAPZC) rather than from the child process
+  // (via TabChild::mApzcTreeManager), so there is no need to check the
+  // layers id against mLayersId (and in any case, it wouldn't match, because
+  // mLayersId stores the parent process's layers id, while nsBaseWidget is
+  // sending the child process's layers id).
+
+  APZThreadUtils::RunOnControllerThread(
+      NewRunnableMethod<ScrollableLayerGuid, ScreenPoint>(
+        "layers::IAPZCTreeManager::StartAutoscroll",
+        mTreeManager,
+        &IAPZCTreeManager::StartAutoscroll,
+        aGuid, aAnchorLocation));
+
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult
+APZCTreeManagerParent::RecvStopAutoscroll(const ScrollableLayerGuid& aGuid)
+{
+  // See RecvStartAutoscroll() for why we don't check the layers id.
+
+  APZThreadUtils::RunOnControllerThread(
+      NewRunnableMethod<ScrollableLayerGuid>(
+        "layers::IAPZCTreeManager::StopAutoscroll",
+        mTreeManager,
+        &IAPZCTreeManager::StopAutoscroll,
+        aGuid));
+
+  return IPC_OK();
+}
+
 mozilla::ipc::IPCResult
 APZCTreeManagerParent::RecvSetLongTapEnabled(const bool& aTapGestureEnabled)
 {

gfx/layers/ipc/APZCTreeManagerParent.h

@@ -126,6 +126,14 @@ public:
           const ScrollableLayerGuid& aGuid,
           const AsyncDragMetrics& aDragMetrics) override;
 
+  mozilla::ipc::IPCResult
+  RecvStartAutoscroll(
+          const ScrollableLayerGuid& aGuid,
+          const ScreenPoint& aAnchorLocation) override;
+
+  mozilla::ipc::IPCResult
+  RecvStopAutoscroll(const ScrollableLayerGuid& aGuid) override;
+
   mozilla::ipc::IPCResult
   RecvSetLongTapEnabled(const bool& aTapGestureEnabled) override;
 

gfx/layers/ipc/PAPZCTreeManager.ipdl

@@ -10,6 +10,7 @@ include "mozilla/dom/TabMessageUtils.h"; // Needed for IPC::ParamTraits<nsEventS
 
 include protocol PCompositorBridge;
 
+using CSSPoint from "Units.h";
 using CSSRect from "Units.h";
 using LayoutDeviceCoord from "Units.h";
 using LayoutDeviceIntPoint from "Units.h";
@@ -79,6 +80,10 @@ parent:
 
   async StartScrollbarDrag(ScrollableLayerGuid aGuid, AsyncDragMetrics aDragMetrics);
 
+  async StartAutoscroll(ScrollableLayerGuid aGuid, ScreenPoint aAnchorLocation);
+
+  async StopAutoscroll(ScrollableLayerGuid aGuid);
+
   async SetLongTapEnabled(bool aTapGestureEnabled);
 
   async ProcessTouchVelocity(uint32_t aTimestampMs, float aSpeedY);

toolkit/content/widgets/browser.xml

@@ -1091,6 +1091,16 @@
                 return false;
               }
               this.startScroll(data.scrolldir, data.screenX, data.screenY);
+              if (this.isRemoteBrowser && data.scrollId != null) {
+                let { tabParent } = this.frameLoader;
+                if (tabParent) {
+                  tabParent.startApzAutoscroll(data.screenX, data.screenY,
+                                               data.scrollId, data.presShellId);
+                }
+                // Save the IDs for later
+                this._autoScrollScrollId = data.scrollId;
+                this._autoScrollPresShellId = data.presShellId;
+              }
               return true;
             }
             case "Autoscroll:Cancel":
@@ -1190,6 +1200,9 @@
       <field name="_startY">null</field>
       <field name="_autoScrollPopup">null</field>
       <field name="_autoScrollNeedsCleanup">false</field>
+      <!-- These IDs identify the scroll frame being autoscrolled. -->
+      <field name="_autoScrollScrollId">null</field>
+      <field name="_autoScrollPresShellId">null</field>
 
       <method name="stopScroll">
         <body>
@@ -1205,6 +1218,16 @@
               window.removeEventListener("keypress", this, true);
               window.removeEventListener("keyup", this, true);
               this.messageManager.sendAsyncMessage("Autoscroll:Stop");
+
+              if (this.isRemoteBrowser) {
+                let { tabParent } = this.frameLoader;
+                if (tabParent) {
+                  tabParent.stopApzAutoscroll(this._autoScrollScrollId,
+                                              this._autoScrollPresShellId);
+                }
+                this._autoScrollScrollId = null;
+                this._autoScrollPresShellId = null;
+              }
             }
          ]]>
        </body>

widget/nsBaseWidget.cpp

@@ -1956,6 +1956,24 @@ nsBaseWidget::StartAsyncScrollbarDrag(const AsyncDragMetrics& aDragMetrics)
       aDragMetrics));
 }
 
+void
+nsBaseWidget::StartAsyncAutoscroll(const ScreenPoint& aAnchorLocation,
+                                   const ScrollableLayerGuid& aGuid)
+{
+  MOZ_ASSERT(XRE_IsParentProcess() && AsyncPanZoomEnabled());
+
+  mAPZC->StartAutoscroll(aGuid, aAnchorLocation);
+}
+
+void
+nsBaseWidget::StopAsyncAutoscroll(const ScrollableLayerGuid& aGuid)
+{
+  MOZ_ASSERT(XRE_IsParentProcess() && AsyncPanZoomEnabled());
+
+  mAPZC->StopAutoscroll(aGuid);
+}
+
+
 already_AddRefed<nsIScreen>
 nsBaseWidget::GetWidgetScreen()
 {

widget/nsBaseWidget.h

@@ -366,6 +366,11 @@ public:
 
   virtual void StartAsyncScrollbarDrag(const AsyncDragMetrics& aDragMetrics) override;
 
+  virtual void StartAsyncAutoscroll(const ScreenPoint& aAnchorLocation,
+                                    const ScrollableLayerGuid& aGuid) override;
+
+  virtual void StopAsyncAutoscroll(const ScrollableLayerGuid& aGuid) override;
+
   /**
    * Use this when GetLayerManager() returns a BasicLayerManager
    * (nsBaseWidget::GetLayerManager() does). This sets up the widget's

widget/nsIWidget.h

@@ -340,6 +340,7 @@ class nsIWidget : public nsISupports
     typedef mozilla::layers::LayerManagerComposite LayerManagerComposite;
     typedef mozilla::layers::LayersBackend LayersBackend;
     typedef mozilla::layers::PLayerTransactionChild PLayerTransactionChild;
+    typedef mozilla::layers::ScrollableLayerGuid ScrollableLayerGuid;
     typedef mozilla::layers::ZoomConstraints ZoomConstraints;
     typedef mozilla::widget::IMEMessage IMEMessage;
     typedef mozilla::widget::IMENotification IMENotification;
@@ -362,6 +363,7 @@ class nsIWidget : public nsISupports
     typedef mozilla::ScreenPoint ScreenPoint;
     typedef mozilla::CSSToScreenScale CSSToScreenScale;
     typedef mozilla::DesktopIntRect DesktopIntRect;
+    typedef mozilla::CSSPoint CSSPoint;
     typedef mozilla::CSSRect CSSRect;
 
     // Used in UpdateThemeGeometries.
@@ -1402,7 +1404,7 @@ class nsIWidget : public nsISupports
      * not need a layers update to process the event.
      */
     virtual void SetConfirmedTargetAPZC(uint64_t aInputBlockId,
-                                        const nsTArray<mozilla::layers::ScrollableLayerGuid>& aTargets) const = 0;
+                                        const nsTArray<ScrollableLayerGuid>& aTargets) const = 0;
 
     /**
      * Returns true if APZ is in use, false otherwise.
@@ -1686,6 +1688,20 @@ class nsIWidget : public nsISupports
 
     virtual void StartAsyncScrollbarDrag(const AsyncDragMetrics& aDragMetrics) = 0;
 
+    /**
+     * Notify APZ to start autoscrolling.
+     * @param aAnchorLocation the location of the autoscroll anchor
+     * @param aGuid identifies the scroll frame to be autoscrolled
+     */
+    virtual void StartAsyncAutoscroll(const ScreenPoint& aAnchorLocation,
+                                      const ScrollableLayerGuid& aGuid) = 0;
+
+    /**
+     * Notify APZ to stop autoscrolling.
+     * @param aGuid identifies the scroll frame which is being autoscrolled.
+     */
+    virtual void StopAsyncAutoscroll(const ScrollableLayerGuid& aGuid) = 0;
+
     // If this widget supports out-of-process compositing, it can override
     // this method to provide additional information to the compositor.
     virtual void GetCompositorWidgetInitData(mozilla::widget::CompositorWidgetInitData* aInitData)