Bug 1304692 - Make puppet widget get coordinate rounding from parent. r=smaug

MozReview-Commit-ID: A3ornUMDmt8

dom/ipc/ContentChild.cpp

@@ -822,14 +822,15 @@ ContentChild::ProvideWindowCommon(TabChild* aTabOpener,
     renderFrame = nullptr;
   }
 
-  ShowInfo showInfo(EmptyString(), false, false, true, false, 0, 0);
+  ShowInfo showInfo(EmptyString(), false, false, true, false, 0, 0, 0);
   auto* opener = nsPIDOMWindowOuter::From(aParent);
   nsIDocShell* openerShell;
   if (opener && (openerShell = opener->GetDocShell())) {
     nsCOMPtr<nsILoadContext> context = do_QueryInterface(openerShell);
     showInfo = ShowInfo(EmptyString(), false,
                         context->UsePrivateBrowsing(), true, false,
-                        aTabOpener->mDPI, aTabOpener->mDefaultScale);
+                        aTabOpener->mDPI, aTabOpener->mRounding,
+                        aTabOpener->mDefaultScale);
   }
 
   // Unfortunately we don't get a window unless we've shown the frame.  That's

dom/ipc/PBrowser.ipdl

@@ -101,6 +101,7 @@ struct ShowInfo
   bool fakeShowInfo;
   bool isTransparent;
   float dpi;
+  int32_t widgetRounding;
   double defaultScale;
 };
 
@@ -375,6 +376,11 @@ parent:
      */
     sync GetDefaultScale() returns (double value);
 
+    /**
+     * Gets the rounding of coordinates in the widget.
+     */
+    sync GetWidgetRounding() returns (int32_t value);
+
     /**
      * Gets maximum of touch points at current device.
      */
@@ -793,7 +799,7 @@ child:
      * value (-1) but in the majority of the cases this saves us from two
      * sync requests from the child to the parent.
      */
-    async UIResolutionChanged(float dpi, double scale);
+    async UIResolutionChanged(float dpi, int32_t rounding, double scale);
 
     /**
      * Tell the child that the system theme has changed, and that a repaint

dom/ipc/TabChild.cpp

@@ -541,6 +541,7 @@ TabChild::TabChild(nsIContentChild* aManager,
   , mDestroyed(false)
   , mUniqueId(aTabId)
   , mDPI(0)
+  , mRounding(0)
   , mDefaultScale(0)
   , mIsTransparent(false)
   , mIPCOpen(false)
@@ -1549,6 +1550,7 @@ TabChild::ApplyShowInfo(const ShowInfo& aInfo)
     }
   }
   mDPI = aInfo.dpi();
+  mRounding = aInfo.widgetRounding();
   mDefaultScale = aInfo.defaultScale();
   mIsTransparent = aInfo.isTransparent();
 }
@@ -2942,6 +2944,22 @@ TabChild::GetDefaultScale(double* aScale)
     SendGetDefaultScale(aScale);
 }
 
+void
+TabChild::GetWidgetRounding(int32_t* aRounding)
+{
+  *aRounding = 1;
+  if (!mRemoteFrame) {
+    return;
+  }
+  if (mRounding > 0) {
+    *aRounding = mRounding;
+    return;
+  }
+
+  // Fallback to a sync call if needed.
+  SendGetWidgetRounding(aRounding);
+}
+
 void
 TabChild::GetMaxTouchPoints(uint32_t* aTouchPoints)
 {
@@ -3285,12 +3303,15 @@ TabChild::RecvRequestNotifyAfterRemotePaint()
 }
 
 bool
-TabChild::RecvUIResolutionChanged(const float& aDpi, const double& aScale)
+TabChild::RecvUIResolutionChanged(const float& aDpi,
+                                  const int32_t& aRounding,
+                                  const double& aScale)
 {
   ScreenIntSize oldScreenSize = GetInnerSize();
   mDPI = 0;
+  mRounding = 0;
   mDefaultScale = 0;
-  static_cast<PuppetWidget*>(mPuppetWidget.get())->UpdateBackingScaleCache(aDpi, aScale);
+  static_cast<PuppetWidget*>(mPuppetWidget.get())->UpdateBackingScaleCache(aDpi, aRounding, aScale);
   nsCOMPtr<nsIDocument> document(GetDocument());
   nsCOMPtr<nsIPresShell> presShell = document->GetShell();
   if (presShell) {

dom/ipc/TabChild.h

@@ -484,6 +484,8 @@ public:
 
   void GetDefaultScale(double *aScale);
 
+  void GetWidgetRounding(int32_t* aRounding);
+
   bool IsTransparent() const { return mIsTransparent; }
 
   void GetMaxTouchPoints(uint32_t* aTouchPoints);
@@ -572,6 +574,7 @@ public:
   }
 
   virtual bool RecvUIResolutionChanged(const float& aDpi,
+                                       const int32_t& aRounding,
                                        const double& aScale) override;
 
   virtual bool
@@ -777,6 +780,7 @@ private:
 
   friend class ContentChild;
   float mDPI;
+  int32_t mRounding;
   double mDefaultScale;
 
   bool mIsTransparent;

dom/ipc/TabParent.cpp

@@ -277,6 +277,7 @@ TabParent::TabParent(nsIContentParent* aManager,
   , mDimensions(0, 0)
   , mOrientation(0)
   , mDPI(0)
+  , mRounding(0)
   , mDefaultScale(0)
   , mUpdatedDimensions(false)
   , mSizeMode(nsSizeMode_Normal)
@@ -1030,7 +1031,8 @@ TabParent::UIResolutionChanged()
     // fails to cache the values, then mDefaultScale.scale might be invalid.
     // We don't want to send that value to content. Just send -1 for it too in
     // that case.
-    Unused << SendUIResolutionChanged(mDPI, mDPI < 0 ? -1.0 : mDefaultScale.scale);
+    Unused << SendUIResolutionChanged(mDPI, mRounding,
+                                      mDPI < 0 ? -1.0 : mDefaultScale.scale);
   }
 }
 
@@ -2499,6 +2501,17 @@ TabParent::RecvGetDefaultScale(double* aValue)
   return true;
 }
 
+bool
+TabParent::RecvGetWidgetRounding(int32_t* aValue)
+{
+  TryCacheDPIAndScale();
+
+  MOZ_ASSERT(mRounding > 0,
+             "Must not ask for rounding before OwnerElement is received!");
+  *aValue = mRounding;
+  return true;
+}
+
 bool
 TabParent::RecvGetMaxTouchPoints(uint32_t* aTouchPoints)
 {
@@ -2766,6 +2779,7 @@ TabParent::TryCacheDPIAndScale()
 
   if (widget) {
     mDPI = widget->GetDPI();
+    mRounding = widget->RoundsWidgetCoordinatesTo();
     mDefaultScale = widget->GetDefaultScale();
   }
 }
@@ -3374,11 +3388,11 @@ TabParent::GetShowInfo()
       nsContentUtils::IsChromeDoc(mFrameElement->OwnerDoc()) &&
       mFrameElement->HasAttr(kNameSpaceID_None, nsGkAtoms::transparent);
     return ShowInfo(name, allowFullscreen, isPrivate, false,
-                    isTransparent, mDPI, mDefaultScale.scale);
+                    isTransparent, mDPI, mRounding, mDefaultScale.scale);
   }
 
   return ShowInfo(EmptyString(), false, false, false,
-                  false, mDPI, mDefaultScale.scale);
+                  false, mDPI, mRounding, mDefaultScale.scale);
 }
 
 void

dom/ipc/TabParent.h

@@ -321,6 +321,8 @@ public:
 
   virtual bool RecvGetDefaultScale(double* aValue) override;
 
+  virtual bool RecvGetWidgetRounding(int32_t* aValue) override;
+
   virtual bool RecvGetMaxTouchPoints(uint32_t* aTouchPoints) override;
 
   virtual bool RecvGetWidgetNativeData(WindowsHandle* aValue) override;
@@ -635,6 +637,7 @@ protected:
   ScreenIntSize mDimensions;
   ScreenOrientationInternal mOrientation;
   float mDPI;
+  int32_t mRounding;
   CSSToLayoutDeviceScale mDefaultScale;
   bool mUpdatedDimensions;
   nsSizeMode mSizeMode;

widget/PuppetWidget.cpp

@@ -79,6 +79,7 @@ PuppetWidget::PuppetWidget(TabChild* aTabChild)
   : mTabChild(aTabChild)
   , mMemoryPressureObserver(nullptr)
   , mDPI(-1)
+  , mRounding(-1)
   , mDefaultScale(-1)
   , mCursorHotspotX(0)
   , mCursorHotspotY(0)
@@ -1194,6 +1195,20 @@ PuppetWidget::GetDefaultScaleInternal()
   return mDefaultScale;
 }
 
+int32_t
+PuppetWidget::RoundsWidgetCoordinatesTo()
+{
+  if (mRounding < 0) {
+    if (mTabChild) {
+      mTabChild->GetWidgetRounding(&mRounding);
+    } else {
+      mRounding = 1;
+    }
+  }
+
+  return mRounding;
+}
+
 void*
 PuppetWidget::GetNativeData(uint32_t aDataType)
 {

widget/PuppetWidget.h

@@ -135,6 +135,8 @@ public:
   virtual LayoutDeviceIntPoint WidgetToScreenOffset() override
   { return LayoutDeviceIntPoint::FromUnknownPoint(GetWindowPosition() + GetChromeDimensions()); }
 
+  int32_t RoundsWidgetCoordinatesTo() override;
+
   void InitEvent(WidgetGUIEvent& aEvent,
                  LayoutDeviceIntPoint* aPoint = nullptr);
 
@@ -202,9 +204,10 @@ public:
 
   virtual TabChild* GetOwningTabChild() override { return mTabChild; }
 
-  void UpdateBackingScaleCache(float aDpi, double aScale)
+  void UpdateBackingScaleCache(float aDpi, int32_t aRounding, double aScale)
   {
     mDPI = aDpi;
+    mRounding = aRounding;
     mDefaultScale = aScale;
   }
 
@@ -358,6 +361,7 @@ private:
 
   // The DPI of the screen corresponding to this widget
   float mDPI;
+  int32_t mRounding;
   double mDefaultScale;
 
   // Precomputed answers for ExecuteNativeKeyBinding