Bug 1574307 - Part 1. Parse viewport-fit in meta element. r=smaug

For safe area insets (cutout) support, CSS Round Display Level 1 (https://drafts.csswg.org/css-round-display/#viewport-fit-descriptor) has new viewport value as `viewport-fit`.

To support safe area insets that is notch on display, CSS Environment Variables Module Level 1 (https://drafts.csswg.org/css-env-1/#safe-area-insets) adds `safearea-insets-*` (left, top, right and bottom). Also, `meta` element has `viewport-fit` enum value. (ex `<meta name="viewport" content="viewport-fit=cover>`) whether web browser window cover notch area.

`viewport-fit` has 3 enum value, `auto`, `cover` and `contain`.  GeckoView wants to expose this value to browser application such Fenix. Because Android API (https://developer.android.com/guide/topics/display-cutout) uses window root layout (It is set by Application) to cover notch on display.

Differential Revision: https://phabricator.services.mozilla.com/D55609

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

dom/base/Document.cpp

@@ -1354,6 +1354,7 @@ Document::Document(const char* aContentType)
       mStackRefCnt(0),
       mUpdateNestLevel(0),
       mViewportType(Unknown),
+      mViewportFit(ViewportFitType::Auto),
       mSubDocuments(nullptr),
       mHeaderData(nullptr),
       mFlashClassification(FlashClassification::Unknown),
@@ -9619,6 +9620,21 @@ nsViewportInfo Document::GetViewportInfo(const ScreenIntSize& aDisplaySize) {
         hasValidContents = true;
       }
 
+      // Resolve viewport-fit value.
+      // https://drafts.csswg.org/css-round-display/#viewport-fit-descriptor
+      mViewportFit = ViewportFitType::Auto;
+      if (!metaData.mViewportFit.IsEmpty()) {
+        if (metaData.mViewportFit.EqualsLiteral("contain")) {
+          mViewportFit = ViewportFitType::Contain;
+          hasValidContents = true;
+        } else if (metaData.mViewportFit.EqualsLiteral("cover")) {
+          mViewportFit = ViewportFitType::Cover;
+          hasValidContents = true;
+        } else if (metaData.mViewportFit.EqualsLiteral("auto")) {
+          hasValidContents = true;
+        }
+      }
+
       mWidthStrEmpty = metaData.mWidth.IsEmpty();
 
       mViewportType = hasValidContents ? Specified : NoValidContent;
@@ -9829,7 +9845,7 @@ nsViewportInfo Document::GetViewportInfo(const ScreenIntSize& aDisplaySize) {
           scaleFloat, scaleMinFloat, scaleMaxFloat, size, sizeFlag,
           mValidScaleFloat ? nsViewportInfo::AutoScaleFlag::FixedScale
                            : nsViewportInfo::AutoScaleFlag::AutoScale,
-          effectiveZoomFlag);
+          effectiveZoomFlag, mViewportFit);
   }
 }
 

dom/base/Document.h

@@ -213,6 +213,7 @@ class SVGUseElement;
 class Touch;
 class TouchList;
 class TreeWalker;
+enum class ViewportFitType : uint8_t;
 class XPathEvaluator;
 class XPathExpression;
 class XPathNSResolver;
@@ -5167,6 +5168,10 @@ class Document : public nsINode,
 
   ViewportType mViewportType;
 
+  // viewport-fit described by
+  // https://drafts.csswg.org/css-round-display/#viewport-fit-descriptor
+  ViewportFitType mViewportFit;
+
   PLDHashTable* mSubDocuments;
 
   DocHeaderData* mHeaderData;

dom/base/ViewportMetaData.cpp

@@ -55,6 +55,8 @@ static void ProcessViewportToken(ViewportMetaData& aData,
     aData.mMaximumScale.Assign(value);
   } else if (key_atom == nsGkAtoms::user_scalable) {
     aData.mUserScalable.Assign(value);
+  } else if (key_atom == nsGkAtoms::viewport_fit) {
+    aData.mViewportFit.Assign(value);
   }
 }
 

dom/base/ViewportMetaData.h

@@ -20,13 +20,15 @@ struct ViewportMetaData {
   nsString mMinimumScale;
   nsString mMaximumScale;
   nsString mUserScalable;
+  nsString mViewportFit;
 
   bool operator==(const ViewportMetaData& aOther) const {
     return mWidth == aOther.mWidth && mHeight == aOther.mHeight &&
            mInitialScale == aOther.mInitialScale &&
            mMinimumScale == aOther.mMinimumScale &&
            mMaximumScale == aOther.mMaximumScale &&
-           mUserScalable == aOther.mUserScalable;
+           mUserScalable == aOther.mUserScalable &&
+           mViewportFit == aOther.mViewportFit;
   }
   bool operator!=(const ViewportMetaData& aOther) const {
     return !(*this == aOther);

dom/base/nsViewportInfo.h

@@ -9,6 +9,16 @@
 #include "mozilla/Attributes.h"
 #include "Units.h"
 
+namespace mozilla {
+namespace dom {
+enum class ViewportFitType : uint8_t {
+  Auto,
+  Contain,
+  Cover,
+};
+}
+}  // namespace mozilla
+
 /**
  * Default values for the nsViewportInfo class.
  */
@@ -39,6 +49,7 @@ class MOZ_STACK_CLASS nsViewportInfo {
                  const mozilla::CSSToScreenScale& aDefaultZoom,
                  ZoomFlag aZoomFlag)
       : mDefaultZoom(aDefaultZoom),
+        mViewportFit(mozilla::dom::ViewportFitType::Auto),
         mDefaultZoomValid(true),
         mAutoSize(true),
         mAllowZoom(aZoomFlag == ZoomFlag::AllowZoom) {
@@ -53,11 +64,13 @@ class MOZ_STACK_CLASS nsViewportInfo {
                  const mozilla::CSSToScreenScale& aMinZoom,
                  const mozilla::CSSToScreenScale& aMaxZoom,
                  const mozilla::CSSSize& aSize, AutoSizeFlag aAutoSizeFlag,
-                 AutoScaleFlag aAutoScaleFlag, ZoomFlag aZoomFlag)
+                 AutoScaleFlag aAutoScaleFlag, ZoomFlag aZoomFlag,
+                 mozilla::dom::ViewportFitType aViewportFit)
       : mDefaultZoom(aDefaultZoom),
         mMinZoom(aMinZoom),
         mMaxZoom(aMaxZoom),
         mSize(aSize),
+        mViewportFit(aViewportFit),
         mDefaultZoomValid(aAutoScaleFlag != AutoScaleFlag::AutoScale),
         mAutoSize(aAutoSizeFlag == AutoSizeFlag::AutoSize),
         mAllowZoom(aZoomFlag == ZoomFlag::AllowZoom) {
@@ -74,6 +87,8 @@ class MOZ_STACK_CLASS nsViewportInfo {
   bool IsAutoSizeEnabled() const { return mAutoSize; }
   bool IsZoomAllowed() const { return mAllowZoom; }
 
+  mozilla::dom::ViewportFitType GetViewportFit() const { return mViewportFit; }
+
   enum {
     Auto = -1,
     ExtendToZoom = -2,
@@ -107,6 +122,9 @@ class MOZ_STACK_CLASS nsViewportInfo {
   // The size of the viewport, specified by the <meta name="viewport"> tag.
   mozilla::CSSSize mSize;
 
+  // The value of the viewport-fit.
+  mozilla::dom::ViewportFitType mViewportFit;
+
   // If the default zoom was specified and was between the min and max
   // zoom values.
   // FIXME: Bug 1504362 - Unify this and mDefaultZoom into

gfx/layers/apz/test/gtest/mvm/TestMobileViewportManager.cpp

@@ -59,7 +59,8 @@ class MockMVMContext : public MVMContext {
                                                     mDisplaySize.width));
     }
     return nsViewportInfo(mDefaultScale, mMinScale, mMaxScale, viewportSize,
-                          mAutoSizeFlag, mAutoScaleFlag, mZoomFlag);
+                          mAutoSizeFlag, mAutoScaleFlag, mZoomFlag,
+                          dom::ViewportFitType::Auto);
   }
   CSSToLayoutDeviceScale CSSToDevPixelScale() const { return mDeviceScale; }
   float GetResolution() const { return mResolution; }

xpcom/ds/StaticAtoms.py

@@ -1245,6 +1245,7 @@ STATIC_ATOMS = [
     Atom("audio", "audio"),
     Atom("video", "video"),
     Atom("viewport", "viewport"),
+    Atom("viewport_fit", "viewport-fit"),
     Atom("viewport_height", "viewport-height"),
     Atom("viewport_initial_scale", "viewport-initial-scale"),
     Atom("viewport_maximum_scale", "viewport-maximum-scale"),