Bug 1588791 - Make fission iframes honor and deal with the scrolling attribute. r=mattwoodrow

Differential Revision: https://phabricator.services.mozilla.com/D59630

--HG--
extra : moz-landing-system : lando

dom/html/nsGenericHTMLFrameElement.cpp

@@ -8,6 +8,7 @@
 
 #include "mozilla/dom/HTMLIFrameElement.h"
 #include "mozilla/dom/XULFrameElement.h"
+#include "mozilla/dom/BrowserBridgeChild.h"
 #include "mozilla/dom/WindowProxyHolder.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/PresShell.h"
@@ -291,10 +292,15 @@ nsresult nsGenericHTMLFrameElement::AfterSetAttr(
   if (aNameSpaceID == kNameSpaceID_None) {
     if (aName == nsGkAtoms::scrolling) {
       if (mFrameLoader) {
-        // FIXME(bug 1588791): This should work for fission iframes.
+        ScrollbarPreference pref = MapScrollingAttribute(aValue);
         if (nsIDocShell* docshell = mFrameLoader->GetExistingDocShell()) {
-          nsDocShell::Cast(docshell)->SetScrollbarPreference(
-              MapScrollingAttribute(aValue));
+          nsDocShell::Cast(docshell)->SetScrollbarPreference(pref);
+        } else if (auto* child = mFrameLoader->GetBrowserBridgeChild()) {
+          // NOTE(emilio): We intentionally don't deal with the
+          // GetBrowserParent() case, and only deal with the fission iframe
+          // case. There's no reason not to make it work, but it's a bit of
+          // boilerplate for something that we don't use...
+          child->SendScrollbarPreferenceChanged(pref);
         }
       }
     } else if (aName == nsGkAtoms::mozbrowser) {

dom/ipc/BrowserBridgeParent.cpp

@@ -143,6 +143,12 @@ IPCResult BrowserBridgeParent::RecvShow(const OwnerShowInfo& aOwnerInfo) {
   return IPC_OK();
 }
 
+IPCResult BrowserBridgeParent::RecvScrollbarPreferenceChanged(
+    ScrollbarPreference aPref) {
+  Unused << mBrowserParent->SendScrollbarPreferenceChanged(aPref);
+  return IPC_OK();
+}
+
 IPCResult BrowserBridgeParent::RecvLoadURL(const nsCString& aUrl) {
   Unused << mBrowserParent->SendLoadURL(aUrl, mBrowserParent->GetShowInfo());
   return IPC_OK();

dom/ipc/BrowserBridgeParent.h

@@ -67,6 +67,7 @@ class BrowserBridgeParent : public PBrowserBridgeParent {
   friend class PBrowserBridgeParent;
 
   mozilla::ipc::IPCResult RecvShow(const OwnerShowInfo&);
+  mozilla::ipc::IPCResult RecvScrollbarPreferenceChanged(ScrollbarPreference);
   mozilla::ipc::IPCResult RecvLoadURL(const nsCString& aUrl);
   mozilla::ipc::IPCResult RecvResumeLoad(uint64_t aPendingSwitchID);
   mozilla::ipc::IPCResult RecvUpdateDimensions(

dom/ipc/BrowserChild.cpp

@@ -1111,7 +1111,8 @@ mozilla::ipc::IPCResult BrowserChild::RecvResumeLoad(
 }
 
 void BrowserChild::DoFakeShow(const ParentShowInfo& aParentShowInfo) {
-  OwnerShowInfo ownerInfo{ScreenIntSize(), mParentIsActive, nsSizeMode_Normal};
+  OwnerShowInfo ownerInfo{ScreenIntSize(), ScrollbarPreference::Auto,
+                          mParentIsActive, nsSizeMode_Normal};
   RecvShow(aParentShowInfo, ownerInfo);
   mDidFakeShow = true;
 }
@@ -1187,6 +1188,7 @@ mozilla::ipc::IPCResult BrowserChild::RecvShow(
 
   ApplyParentShowInfo(aParentInfo);
   RecvParentActivated(aOwnerInfo.parentWindowIsActive());
+  RecvScrollbarPreferenceChanged(aOwnerInfo.scrollbarPreference());
 
   if (!res) {
     return IPC_FAIL_NO_REASON(this);
@@ -1213,6 +1215,13 @@ mozilla::ipc::IPCResult BrowserChild::RecvInitRendering(
   return IPC_OK();
 }
 
+mozilla::ipc::IPCResult BrowserChild::RecvScrollbarPreferenceChanged(
+    ScrollbarPreference aPreference) {
+  nsCOMPtr<nsIDocShell> docShell = do_GetInterface(WebNavigation());
+  nsDocShell::Cast(docShell)->SetScrollbarPreference(aPreference);
+  return IPC_OK();
+}
+
 mozilla::ipc::IPCResult BrowserChild::RecvCompositorOptionsChanged(
     const CompositorOptions& aNewOptions) {
   MOZ_ASSERT(mCompositorOptions);

dom/ipc/BrowserChild.h

@@ -702,6 +702,8 @@ class BrowserChild final : public nsMessageManagerScriptExecutor,
 
   mozilla::ipc::IPCResult RecvParentActivated(const bool& aActivated);
 
+  mozilla::ipc::IPCResult RecvScrollbarPreferenceChanged(ScrollbarPreference);
+
   mozilla::ipc::IPCResult RecvSetKeyboardIndicators(
       const UIStateChangeType& aShowFocusRings);
 

dom/ipc/DOMTypes.ipdlh

@@ -29,6 +29,7 @@ using CSSSize from "Units.h";
 using ScreenIntSize from "Units.h";
 using mozilla::LayoutDeviceIntPoint from "Units.h";
 using nsSizeMode from "nsIWidgetListener.h";
+using ScrollbarPreference from "mozilla/ScrollbarPreferences.h";
 using hal::ScreenOrientation from "mozilla/HalScreenConfiguration.h";
 using mozilla::gfx::SurfaceFormat from "mozilla/gfx/Types.h";
 using refcounted class nsIPrincipal from "mozilla/dom/PermissionMessageUtils.h";
@@ -354,7 +355,8 @@ struct OwnerShowInfo {
   // render to a virtual <0, 0> top-left point.
   ScreenIntSize size;
 
-  // TODO(emilio): Scrollbar and margin preferences go here.
+  // TODO(emilio): Margin preferences go here.
+  ScrollbarPreference scrollbarPreference;
 
   // TODO(emilio): I think we should really be able to figure out these from the
   // parent process too instead.

dom/ipc/DocShellMessageUtils.h

@@ -10,6 +10,7 @@
 #include "ipc/IPCMessageUtils.h"
 #include "nsCOMPtr.h"
 #include "nsDocShellLoadState.h"
+#include "mozilla/ScrollbarPreferences.h"
 
 namespace mozilla {
 namespace ipc {
@@ -25,4 +26,14 @@ struct IPDLParamTraits<nsDocShellLoadState*> {
 }  // namespace ipc
 }  // namespace mozilla
 
+namespace IPC {
+
+template <>
+struct ParamTraits<mozilla::ScrollbarPreference>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::ScrollbarPreference, mozilla::ScrollbarPreference::Auto,
+          mozilla::ScrollbarPreference::LAST> {};
+
+}  // namespace IPC
+
 #endif  // mozilla_dom_docshell_message_utils_h__

dom/ipc/PBrowser.ipdl

@@ -718,6 +718,8 @@ child:
      */
     async Show(ParentShowInfo parentInfo, OwnerShowInfo childInfo);
 
+    async ScrollbarPreferenceChanged(ScrollbarPreference pref);
+
     async InitRendering(TextureFactoryIdentifier textureFactoryIdentifier,
                         LayersId layersId,
                         CompositorOptions compositorOptions,

dom/ipc/PBrowserBridge.ipdl

@@ -77,6 +77,7 @@ parent:
 
   // Out of process rendering.
   async Show(OwnerShowInfo info);
+  async ScrollbarPreferenceChanged(ScrollbarPreference pref);
   async UpdateDimensions(DimensionInfo dimensions) compressall;
   async RenderLayers(bool aEnabled, LayersObserverEpoch aEpoch);
 

layout/generic/ScrollbarPreferences.h

@@ -14,6 +14,7 @@ namespace mozilla {
 enum class ScrollbarPreference : uint8_t {
   Auto,
   Never,
+  LAST = Never,
 };
 
 }  // namespace mozilla

layout/reftests/scrolling/reftest.list

@@ -34,10 +34,10 @@ fuzzy-if(Android,0-5,0-20000) == uncovering-2.html uncovering-2-ref.html
 fuzzy-if(asyncPan&&!layersGPUAccelerated,0-149,0-4520) == less-than-scrollbar-height.html less-than-scrollbar-height-ref.html
 == huge-horizontal-overflow.html huge-horizontal-overflow-ref.html
 == huge-vertical-overflow.html huge-vertical-overflow-ref.html
-fuzzy-if(asyncPan&&!layersGPUAccelerated,0-102,0-6818) fails-if(browserIsFission) == iframe-scrolling-attr-1.html iframe-scrolling-attr-ref.html # Fission failure bug 1588791
-fuzzy-if(asyncPan&&!layersGPUAccelerated,0-140,0-6818) fails-if(browserIsFission) == iframe-scrolling-attr-2.html iframe-scrolling-attr-ref.html
-fuzzy(0-1,0-2) fuzzy-if(geckoview,0-1,0-15) fails-if(browserIsFission) == frame-scrolling-attr-1.html frame-scrolling-attr-ref.html
-fuzzy(0-1,0-2) fuzzy-if(asyncPan&&!layersGPUAccelerated,0-102,0-2420) fuzzy-if(geckoview,0-1,0-88) fails-if(browserIsFission) == frame-scrolling-attr-2.html frame-scrolling-attr-ref.html
+fuzzy-if(asyncPan&&!layersGPUAccelerated,0-102,0-6818) == iframe-scrolling-attr-1.html iframe-scrolling-attr-ref.html
+fuzzy-if(asyncPan&&!layersGPUAccelerated,0-140,0-6818) == iframe-scrolling-attr-2.html iframe-scrolling-attr-ref.html
+fuzzy(0-1,0-2) fuzzy-if(geckoview,0-1,0-15) == frame-scrolling-attr-1.html frame-scrolling-attr-ref.html
+fuzzy(0-1,0-2) fuzzy-if(asyncPan&&!layersGPUAccelerated,0-102,0-2420) fuzzy-if(geckoview,0-1,0-88) == frame-scrolling-attr-2.html frame-scrolling-attr-ref.html
 == move-item.html move-item-ref.html # bug 1125750
 == fractional-scroll-area.html?top=-0.4&outerBottom=100&innerBottom=200 fractional-scroll-area.html?top=0&outerBottom=100&innerBottom=200
 == fractional-scroll-area.html?top=0.4&outerBottom=100&innerBottom=200 fractional-scroll-area.html?top=0&outerBottom=100&innerBottom=200