Bug 1503656 - Part 5. Get safe area insets from Gecko. r=emilio

Add binding to get safe area insets from Gecko.

Differential Revision: https://phabricator.services.mozilla.com/D52509

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

layout/base/nsPresContext.cpp

@@ -2580,6 +2580,10 @@ DynamicToolbarState nsPresContext::GetDynamicToolbarState() const {
   return DynamicToolbarState::InTransition;
 }
 
+void nsPresContext::SetSafeAreaInsets(const ScreenIntMargin& aSafeAreaInsets) {
+  mSafeAreaInsets = aSafeAreaInsets;
+}
+
 #ifdef DEBUG
 
 void nsPresContext::ValidatePresShellAndDocumentReleation() const {

layout/base/nsPresContext.h

@@ -494,6 +494,13 @@ class nsPresContext : public nsISupports,
     UpdateEffectiveTextZoom();
   }
 
+  /**
+   * Notify the pres context that the safe area insets have changed.
+   */
+  void SetSafeAreaInsets(const mozilla::ScreenIntMargin& aInsets);
+
+  mozilla::ScreenIntMargin GetSafeAreaInsets() const { return mSafeAreaInsets; }
+
  protected:
   void UpdateEffectiveTextZoom();
 
@@ -596,7 +603,7 @@ class nsPresContext : public nsISupports,
     return AppUnitsToIntCSSPixels(DevPixelsToAppUnits(aPixels));
   }
 
-  float DevPixelsToFloatCSSPixels(int32_t aPixels) {
+  float DevPixelsToFloatCSSPixels(int32_t aPixels) const {
     return AppUnitsToFloatCSSPixels(DevPixelsToAppUnits(aPixels));
   }
 
@@ -1210,6 +1217,8 @@ class nsPresContext : public nsISupports,
   // The maximum height of the dynamic toolbar on mobile.
   mozilla::ScreenIntCoord mDynamicToolbarMaxHeight;
   mozilla::ScreenIntCoord mDynamicToolbarHeight;
+  // Safe area insets support
+  mozilla::ScreenIntMargin mSafeAreaInsets;
   nsSize mPageSize;
   float mPageScale;
   float mPPScale;

layout/style/GeckoBindings.cpp

@@ -1744,6 +1744,16 @@ bool Gecko_AssertClassAttrValueIsSane(const nsAttrValue* aValue) {
   return true;
 }
 
+void Gecko_GetSafeAreaInsets(const nsPresContext* aPresContext, float* aTop,
+                             float* aRight, float* aBottom, float* aLeft) {
+  MOZ_ASSERT(aPresContext);
+  ScreenIntMargin safeAreaInsets = aPresContext->GetSafeAreaInsets();
+  *aTop = aPresContext->DevPixelsToFloatCSSPixels(safeAreaInsets.top);
+  *aRight = aPresContext->DevPixelsToFloatCSSPixels(safeAreaInsets.right);
+  *aBottom = aPresContext->DevPixelsToFloatCSSPixels(safeAreaInsets.bottom);
+  *aLeft = aPresContext->DevPixelsToFloatCSSPixels(safeAreaInsets.left);
+}
+
 void Gecko_PrintfStderr(const nsCString* aStr) {
   printf_stderr("%s", aStr->get());
 }

layout/style/GeckoBindings.h

@@ -633,6 +633,9 @@ bool Gecko_MediaFeatures_IsResourceDocument(const mozilla::dom::Document*);
 nsAtom* Gecko_MediaFeatures_GetOperatingSystemVersion(
     const mozilla::dom::Document*);
 
+void Gecko_GetSafeAreaInsets(const nsPresContext*, float*, float*, float*,
+                             float*);
+
 void Gecko_PrintfStderr(const nsCString*);
 
 }  // extern "C"

servo/components/style/gecko/media_queries.rs

@@ -310,6 +310,15 @@ impl Device {
 
     /// Returns safe area insets
     pub fn safe_area_insets(&self) -> SideOffsets2D<f32, CSSPixel> {
-        SideOffsets2D::zero()
+        let pc = match self.pres_context() {
+            Some(pc) => pc,
+            None => return SideOffsets2D::zero(),
+        };
+        let mut top = 0.0;
+        let mut right = 0.0;
+        let mut bottom = 0.0;
+        let mut left = 0.0;
+        unsafe { bindings::Gecko_GetSafeAreaInsets(pc, &mut top, &mut right, &mut bottom, &mut left) };
+        SideOffsets2D::new(top, right, bottom, left)
     }
 }