Implemented -zen-window-transform-origin attribute and applied it to the panels on the right side

src/browser/base/content/zen-styles/zen-panel-ui.css

@@ -6,6 +6,19 @@
 panel[type='arrow'][animate='open'] {
   @media (-moz-platform: macos) {
     animation: zen-jello-animation-macos 0.4s ease-out;
+    &[side='bottom'] {
+      /* Animate from the bottom */
+      -zen-window-transform-origin: 0 100%;
+    }
+    :root[zen-right-side='true'] & {
+      /* Animate from the right */
+      -zen-window-transform-origin: 100% 0;
+
+      &[side='bottom'] {
+        /* Animate from the bottom right */
+        -zen-window-transform-origin: 100% 100%;
+      }
+    }
   }
   @media (-moz-platform: linux) or ((-moz-platform: windows) and (not (-moz-windows-mica-popups))) {
     /* Mica popups have a weird background while the animation is running */

src/browser/base/zen-components/ZenGlanceManager.mjs

@@ -551,6 +551,8 @@
 
     async fullyOpenGlance({ forSplit = false } = {}) {
       this.animatingFullOpen = true;
+      this.#currentTab.removeAttribute('zen-glance-tab');
+
       gBrowser._insertTabAtIndex(this.#currentTab, {
         index: this.getTabPosition(this.#currentTab),
       });
@@ -558,7 +560,6 @@
       this._clearContainerStyles(this.browserWrapper);
       this.browserWrapper.removeAttribute('has-finished-animation');
       this.browserWrapper.setAttribute('animate-full', true);
-      this.#currentTab.removeAttribute('zen-glance-tab');
       this.#currentTab.removeAttribute('glance-id');
       this.#currentParentTab.removeAttribute('glance-id');
       gBrowser.selectedTab = this.#currentTab;

src/devtools/server/actors/animation-type-longhand-js.patch

@@ -0,0 +1,12 @@
+diff --git a/devtools/server/actors/animation-type-longhand.js b/devtools/server/actors/animation-type-longhand.js
+index a7faa2a2f17144198338aa80207ccf33b631cf32..7c15f8d8d533721b661866643cf10b37c99cb051 100644
+--- a/devtools/server/actors/animation-type-longhand.js
++++ b/devtools/server/actors/animation-type-longhand.js
+@@ -341,6 +341,7 @@ exports.ANIMATION_TYPE_FOR_LONGHANDS = [
+       "transform-origin",
+       "translate",
+       "-moz-window-transform",
++      "-zen-window-transform-origin",
+       "-webkit-line-clamp",
+     ]),
+   ],

src/dom/base/use_counter_metrics-yaml.patch

@@ -0,0 +1,50 @@
+diff --git a/dom/base/use_counter_metrics.yaml b/dom/base/use_counter_metrics.yaml
+index ffdb908e5760eea8643f3c3f85979cb5f7ff36ae..8ab16b5283f8c15f20b0d630a9b5fc82ec803af5 100644
+--- a/dom/base/use_counter_metrics.yaml
++++ b/dom/base/use_counter_metrics.yaml
+@@ -21289,6 +21289,22 @@ use.counter.css.page:
+     send_in_pings:
+       - use-counters
+ 
++  css_zen_window_transform_origin:
++    type: counter
++    description: >
++      Whether a page used the CSS property -zen-window-transform-origin.
++      Compare against `use.counter.top_level_content_documents_destroyed`
++      to calculate the rate.
++    bugs:
++      - https://bugzilla.mozilla.org/show_bug.cgi?id=1852098
++    data_reviews:
++      - https://bugzilla.mozilla.org/show_bug.cgi?id=1852098
++    notification_emails:
++      - dom-core@mozilla.com
++    expires: never
++    send_in_pings:
++      - use-counters
++
+   css_transform_origin:
+     type: counter
+     description: >
+@@ -33259,6 +33275,22 @@ use.counter.css.doc:
+     send_in_pings:
+       - use-counters
+ 
++  css_zen_window_transform_origin:
++    type: counter
++    description: >
++      Whether a document used the CSS property -zen-window-transform-origin.
++      Compare against `use.counter.content_documents_destroyed`
++      to calculate the rate.
++    bugs:
++      - https://bugzilla.mozilla.org/show_bug.cgi?id=1852098
++    data_reviews:
++      - https://bugzilla.mozilla.org/show_bug.cgi?id=1852098
++    notification_emails:
++      - dom-core@mozilla.com
++    expires: never
++    send_in_pings:
++      - use-counters
++
+   css_transform_origin:
+     type: counter
+     description: >

src/layout/generic/nsIFrame-cpp.patch

@@ -0,0 +1,16 @@
+diff --git a/layout/generic/nsIFrame.cpp b/layout/generic/nsIFrame.cpp
+index 01f724b0c42999107c4622323f849ddd2a6fe5c9..9dafa755c711c43c11835dfe9f7ba1b70b52b9a3 100644
+--- a/layout/generic/nsIFrame.cpp
++++ b/layout/generic/nsIFrame.cpp
+@@ -11694,6 +11694,11 @@ gfx::Matrix nsIFrame::ComputeWidgetTransform() const {
+   gfx::Matrix4x4 matrix = nsStyleTransformMatrix::ReadTransforms(
+       uiReset->mMozWindowTransform, refBox, float(appUnitsPerDevPixel));
+ 
++  const StyleTransformOrigin& origin = uiReset->mWindowTransformOrigin;
++  Point transformOrigin = nsStyleTransformMatrix::Convert2DPosition(
++      origin.horizontal, origin.vertical, refBox, appUnitsPerDevPixel);
++  matrix.ChangeBasis(Point3D(transformOrigin.x, transformOrigin.y, 0));
++
+   gfx::Matrix result2d;
+   if (!matrix.CanDraw2D(&result2d)) {
+     // FIXME: It would be preferable to reject non-2D transforms at parse time.

src/layout/style/nsStyleStruct-cpp.patch

@@ -0,0 +1,22 @@
+diff --git a/layout/style/nsStyleStruct.cpp b/layout/style/nsStyleStruct.cpp
+index f89bade8099183baa55b38ccc3c77c7ba9f1a290..8ada58a7965e7f2c9375d8b9bf64a5c78d80bf3f 100644
+--- a/layout/style/nsStyleStruct.cpp
++++ b/layout/style/nsStyleStruct.cpp
+@@ -3204,6 +3204,9 @@ nsStyleUIReset::nsStyleUIReset()
+       mWindowShadow(StyleWindowShadow::Auto),
+       mWindowOpacity(1.0),
+       mMozWindowInputRegionMargin(StyleLength::Zero()),
++      mWindowTransformOrigin{LengthPercentage::FromPercentage(0.5),
++                                   LengthPercentage::FromPercentage(0.5),
++                                   {0.}},
+       mTransitions(
+           nsStyleAutoArray<StyleTransition>::WITH_SINGLE_INITIAL_ELEMENT),
+       mTransitionTimingFunctionCount(1),
+@@ -3247,6 +3250,7 @@ nsStyleUIReset::nsStyleUIReset(const nsStyleUIReset& aSource)
+       mWindowOpacity(aSource.mWindowOpacity),
+       mMozWindowInputRegionMargin(aSource.mMozWindowInputRegionMargin),
+       mMozWindowTransform(aSource.mMozWindowTransform),
++      mWindowTransformOrigin(aSource.mWindowTransformOrigin),
+       mTransitions(aSource.mTransitions.Clone()),
+       mTransitionTimingFunctionCount(aSource.mTransitionTimingFunctionCount),
+       mTransitionDurationCount(aSource.mTransitionDurationCount),

src/layout/style/nsStyleStruct-h.patch

@@ -0,0 +1,12 @@
+diff --git a/layout/style/nsStyleStruct.h b/layout/style/nsStyleStruct.h
+index 97eed3431394e21eb7b8890fd87aea8240e23f2b..898d5876c03f822e9e0f2ec892ee86e0d17daf73 100644
+--- a/layout/style/nsStyleStruct.h
++++ b/layout/style/nsStyleStruct.h
+@@ -1875,6 +1875,7 @@ struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleUIReset {
+   // The margin of the window region that should be transparent to events.
+   mozilla::StyleLength mMozWindowInputRegionMargin;
+   mozilla::StyleTransform mMozWindowTransform;
++  mozilla::StyleTransformOrigin mWindowTransformOrigin;
+ 
+   nsStyleAutoArray<mozilla::StyleTransition> mTransitions;
+   // The number of elements in mTransitions that are not from repeating

src/layout/style/test/ListCSSProperties-cpp.patch

@@ -0,0 +1,12 @@
+diff --git a/layout/style/test/ListCSSProperties.cpp b/layout/style/test/ListCSSProperties.cpp
+index b6a881b037a3720991f8097903e859dfc72012c1..8917a8cc23b97e37b4accaaf0d6c2876b36594af 100644
+--- a/layout/style/test/ListCSSProperties.cpp
++++ b/layout/style/test/ListCSSProperties.cpp
+@@ -108,6 +108,7 @@ const char* gInaccessibleProperties[] = {
+     "-moz-window-opacity",                // chrome-only internal properties
+     "-moz-window-transform",              // chrome-only internal properties
+     "-moz-window-shadow",                 // chrome-only internal properties
++    "-zen-window-transform-origin",       // chrome-only internal properties
+ };
+ 
+ inline int is_inaccessible(const char* aPropName) {

src/servo/components/style/properties/longhands/ui-mako-rs.patch

@@ -0,0 +1,23 @@
+diff --git a/servo/components/style/properties/longhands/ui.mako.rs b/servo/components/style/properties/longhands/ui.mako.rs
+index b7d24fe7bb54b1c143876e3bc9da59c64324ffa5..c36f7edcf076e31209e847af0b59361033d3b4da 100644
+--- a/servo/components/style/properties/longhands/ui.mako.rs
++++ b/servo/components/style/properties/longhands/ui.mako.rs
+@@ -286,6 +286,18 @@ ${helpers.predefined_type(
+     affects="",
+ )}
+ 
++${helpers.predefined_type(
++    "-zen-window-transform-origin",
++    "TransformOrigin",
++    "computed::TransformOrigin::initial_value()",
++    engines="gecko",
++    gecko_ffi_name="mWindowTransformOrigin",
++    boxed=True,
++    spec="None (Nonstandard internal property)",
++    enabled_in="chrome",
++    affects="overflow",
++)}
++
+ ${helpers.predefined_type(
+     "animation-fill-mode",
+     "AnimationFillMode",