Started working on split views!

src/browser/app/profile/zen-browser.js

@@ -141,3 +141,6 @@ pref('dom.security.sanitizer.enabled', true);
 pref('zen.sidebar.data', "{\"data\":\n {\"p1\":{\n   \"url\":\"https://www.wikipedia.org/\"\n  },\n\"p2\":{\n   \"url\":\"https://m.twitter.com/\",\n\"ua\": true\n  },\n\"p3\": {\n   \"url\": \"https://www.youtube.com/\",\n\"ua\": true\n},\n\"p4\": {\n   \"url\": \"https://translate.google.com/\",\n\"ua\": true\n},\n\"p5\": {\n   \"url\": \"https://todoist.com/\",\n\"ua\": true\n}},\n\"index\":[\"p1\",\"p2\",\"p3\",\"p4\",\"p5\"]}");
 pref('zen.sidebar.enabled', true);
 pref('zen.sidebar.floating', true);
+
+// Zen Split View
+pref('zen.splitView.working', false);

src/browser/base/content/ZenViewSplitter.mjs

@@ -3,7 +3,6 @@ var gZenViewSplitter = {
   /**
    * [ 
    *   {
-   *     view: <element>,
    *     tabs: [
    *      tab1,
    *      tab2,
@@ -16,19 +15,15 @@ var gZenViewSplitter = {
   currentView: -1,
 
   init() {
-    return;
+    Services.prefs.setBoolPref("zen.splitView.working", false);
     window.addEventListener("TabClose", this);
-    window.addEventListener("TabChange", this);
+    console.log("ZenViewSplitter initialized");
   },
 
   handleEvent(event) {
     switch (event.type) {
       case "TabClose":
         this.onTabClose(event);
-        break;
-      case "TabChange":
-        this.onTabChange(event);
-        break;
     }
   },
 
@@ -54,62 +49,85 @@ var gZenViewSplitter = {
     this._showSplitView(tab);
   },
 
-  onTabChange(event) {
-    const tab = event.target;
-    this._showSplitView(tab);
+  onLocationChange(browser) {
+    if (!Services.prefs.getBoolPref("zen.splitView.working")) {
+      return;
+    }
+    let tab = gBrowser.getTabForBrowser(browser);
+    if (!tab) {
+      return;
+    }
+    if (tab._zenSplitted) {
+      this._showSplitView(tab);
+    }
   },
 
   splitTabs(tabs) {
     if (tabs.length < 2) {
       return;
     }
-    let gridElement = document.createElement("div");
-    gridElement.classList.add("zen-deck");
-    tabs.forEach((tab) => {
-      let container = tab.linkedBrowser.closest(".browserContainer");
-      gridElement.appendChild(container);
-    });
-    this.tabBrowserPanel.appendChild(gridElement);
     this._data.push({
       tabs,
-      element: gridElement,
     });
     this._showSplitView(tabs[0]);
   },
 
   _showSplitView(tab) {
-    if (this.currentView !== -1) {
-      this._data[this.currentView].element.classList.remove("deck-selected");
+    const splitData = this._data.find((group) => group.tabs.includes(tab));
+    function modifyDecks(tabs, add) {
+      for (const tab of tabs) {
+        if (tab.linkedBrowser.docShellIsActive !== add) {
+          tab.linkedBrowser.docShellIsActive = add;
+        }
+        let browser = tab.linkedBrowser.closest(".browserSidebarContainer");
+        if (add) {
+          browser.classList.add("deck-selected");
+          continue;
+        }
+        browser.classList.remove("deck-selected");
+      }
+      setTimeout((() => {
+        modifyDecks(tabs, add);
+      }).bind(tabs, add), 300);
+    }
+    const handleClick = (tab) => {
+      return ((event) => {
+        gBrowser.selectedTab = tab;
+      })
+    };
+    if (!splitData) {
+      if (this.currentView < 0) {
+        return;
+      }
       for (const tab of this._data[this.currentView].tabs) {
         tab._zenSplitted = false;
         let container = tab.linkedBrowser.closest(".browserSidebarContainer");
+        container.removeAttribute("zen-split-active");
         console.assert(container, "No container found for tab");
-        container.classList.remove("deck-selected");
         container.removeAttribute("zen-split");
+        container.removeEventListener("click", handleClick(tab));
       }
-    }
-    const splitData = this._data.find((group) => group.tabs.includes(tab));
-    console.log(splitData)
-    if (!splitData) {
+      this.tabBrowserPanel.removeAttribute("zen-split-view");
+      Services.prefs.setBoolPref("zen.splitView.working", false);
+      modifyDecks(this._data[this.currentView].tabs, false);
+      this.currentView = -1;
       return;
     }
+    this.tabBrowserPanel.setAttribute("zen-split-view", "true");
+    Services.prefs.setBoolPref("zen.splitView.working", true);
     this.currentView = this._data.indexOf(splitData);
-    splitData.element.classList.add("deck-selected");
-    for (const tab of splitData.tabs) {
-      tab._zenSplitted = true;
-      let container = tab.linkedBrowser.closest(".browserSidebarContainer");
+    for (const _tab of splitData.tabs) {
+      _tab._zenSplitted = true;
+      let container = _tab.linkedBrowser.closest(".browserSidebarContainer");
+      container.removeAttribute("zen-split-active");
+      if (_tab == tab) {
+        container.setAttribute("zen-split-active", "true");
+      }
+      container.addEventListener("click", handleClick(_tab));
       console.assert(container, "No container found for tab");
-      container.classList.add("deck-selected");
       container.setAttribute("zen-split", "true");
     }
-    if (splitData.tabs.length < 2) {
-      let tab = splitData.tabs[0];
-      tab._zenSplitted = false;
-      let container = tab.linkedBrowser.closest(".browserSidebarContainer");
-      console.assert(container, "No container found for tab");
-      this.tabBrowserPanel.appendChild(container);
-      splitData.element.remove();
-    }
+    modifyDecks(splitData.tabs, true);
   },
 };
 

src/browser/base/content/tabbrowser-js.patch

@@ -0,0 +1,13 @@
+diff --git a/browser/base/content/tabbrowser.js b/browser/base/content/tabbrowser.js
+index 3bca0b6d30468dc3a755219723f673ec80dfce6e..6dd39545115f57ab2aedb9f8aad79ee35466a4c7 100644
+--- a/browser/base/content/tabbrowser.js
++++ b/browser/base/content/tabbrowser.js
+@@ -1349,6 +1349,8 @@
+       if (!aForceUpdate) {
+         TelemetryStopwatch.finish("FX_TAB_SWITCH_UPDATE_MS");
+       }
++
++      gZenViewSplitter.onLocationChange(newBrowser);
+     },
+ 
+     _adjustFocusBeforeTabSwitch(oldTab, newTab) {

src/browser/modules/AsyncTabSwitcher-sys-mjs.patch

@@ -0,0 +1,68 @@
+diff --git a/browser/modules/AsyncTabSwitcher.sys.mjs b/browser/modules/AsyncTabSwitcher.sys.mjs
+index 9f4aa535e07adab496788165f4089be6732b1444..7b7955c0d1f2f3277cb750652458649d181e90e5 100644
+--- a/browser/modules/AsyncTabSwitcher.sys.mjs
++++ b/browser/modules/AsyncTabSwitcher.sys.mjs
+@@ -39,6 +39,10 @@ XPCOMUtils.defineLazyPreferenceGetter(
+   300
+ );
+ 
++function zenSplitViewIsEnabled() {
++  return Services.prefs.getBoolPref("zen.splitView.working", false);
++}
++
+ /**
+  * The tab switcher is responsible for asynchronously switching
+  * tabs in e10s. It waits until the new tab is ready (i.e., the
+@@ -279,7 +283,7 @@ export class AsyncTabSwitcher {
+         browser.docShellIsActive = true;
+       }
+ 
+-      if (remoteTab) {
++      if (remoteTab && !zenSplitViewIsEnabled()) {
+         browser.renderLayers = true;
+         remoteTab.priorityHint = true;
+       }
+@@ -291,7 +295,7 @@ export class AsyncTabSwitcher {
+       // Setting the docShell to be inactive will also cause it
+       // to stop rendering layers.
+       browser.docShellIsActive = false;
+-      if (remoteTab) {
++      if (remoteTab && !zenSplitViewIsEnabled()) {
+         remoteTab.priorityHint = false;
+       }
+       if (!browser.hasLayers) {
+@@ -364,7 +368,7 @@ export class AsyncTabSwitcher {
+     // constructing BrowserChild's, layer trees, etc, by showing a blank
+     // tab instead and focusing it immediately.
+     let shouldBeBlank = false;
+-    if (requestedBrowser.isRemoteBrowser) {
++    if (requestedBrowser.isRemoteBrowser && !zenSplitViewIsEnabled()) {
+       // If a tab is remote and the window is not minimized, we can show a
+       // blank tab instead of a spinner in the following cases:
+       //
+@@ -399,7 +403,7 @@ export class AsyncTabSwitcher {
+       }
+     }
+ 
+-    if (requestedBrowser.isRemoteBrowser) {
++    if (requestedBrowser.isRemoteBrowser && !zenSplitViewIsEnabled()) {
+       this.addLogFlag("isRemote");
+     }
+ 
+@@ -825,7 +829,7 @@ export class AsyncTabSwitcher {
+       `onRemotenessChange(${tab._tPos}, ${tab.linkedBrowser.isRemoteBrowser})`
+     );
+     if (!tab.linkedBrowser.isRemoteBrowser) {
+-      if (this.getTabState(tab) == this.STATE_LOADING) {
++      if (this.getTabState(tab) == this.STATE_LOADING && !zenSplitViewIsEnabled()) {
+         this.onLayersReady(tab.linkedBrowser);
+       } else if (this.getTabState(tab) == this.STATE_UNLOADING) {
+         this.onLayersCleared(tab.linkedBrowser);
+@@ -1018,6 +1022,7 @@ export class AsyncTabSwitcher {
+       lazy.gTabCacheSize > 1 &&
+       tab.linkedBrowser.isRemoteBrowser &&
+       tab.linkedBrowser.currentURI.spec != "about:blank"
++      && !zenSplitViewIsEnabled()
+     ) {
+       let tabIndex = this.tabLayerCache.indexOf(tab);
+ 

src/browser/themes/shared/zen-decks.css

@@ -1,14 +1,20 @@
 
 /** Zen Decks - ONLY USED FOR SPLIT VIEWS, DO NOT USE THIS CLASS FOR ANY OTHER PURPOSE **/
 
-.zen-deck {
-  display: grid;
-  position: absolute;
-  width: 100%;
-  height: 100%;
+#tabbrowser-tabpanels[zen-split-view="true"] {
+  display: flex;
+  flex-direction: row;
 }
 
-.zen-deck:not(.deck-selected) {
-  z-index: -1;
-  visibility: hidden;
+#tabbrowser-tabpanels[zen-split-view="true"] > *:not(.deck-selected) {
+  flex: 0;
+  margin: 0 !important;
 }
+
+#tabbrowser-tabpanels[zen-split-view="true"] > .deck-selected {
+  flex: 1;
+}
+
+#tabbrowser-tabpanels[zen-split-view="true"] .browserSidebarContainer[zen-split-active="true"] {
+  border-color: var(--zen-primary-color) !important;
+}

src/dom/ipc/BrowserHost-cpp.patch

@@ -0,0 +1,13 @@
+diff --git a/dom/ipc/BrowserHost.cpp b/dom/ipc/BrowserHost.cpp
+index 489f07a612e52a3edb00f59e53495dcd9e16c0f5..1799e0d416f9d7be2c9e34c237d6ff741e5e2420 100644
+--- a/dom/ipc/BrowserHost.cpp
++++ b/dom/ipc/BrowserHost.cpp
+@@ -106,7 +106,7 @@ void BrowserHost::UpdateEffects(EffectsInfo aEffects) {
+ /* attribute boolean renderLayers; */
+ NS_IMETHODIMP
+ BrowserHost::GetRenderLayers(bool* aRenderLayers) {
+-  if (!mRoot) {
++  if (!mRoot && !Preferences::GetBool("zen.splitView.working", false)) {
+     *aRenderLayers = false;
+     return NS_OK;
+   }