Bug 1240326 - Part 1: Add lazyWidth and lazyHeight properties to frame loaders. r=billm

MozReview-Commit-ID: 6uEcjS10KCW

--HG--
extra : transplant_source : 9%A0I%8Dl%FB%7EQK%8C%E3k%8F%15W%BCA%12p%1D

dom/base/nsFrameLoader.cpp

@@ -2280,6 +2280,7 @@ nsFrameLoader::UpdatePositionAndSize(nsSubDocumentFrame *aIFrame)
       ScreenIntSize size = aIFrame->GetSubdocumentSize();
       nsIntRect dimensions;
       NS_ENSURE_SUCCESS(GetWindowDimensions(dimensions), NS_ERROR_FAILURE);
+      mLazySize = size;
       mRemoteBrowser->UpdateDimensions(dimensions, size);
     }
     return NS_OK;
@@ -2310,11 +2311,38 @@ nsFrameLoader::UpdateBaseWindowPositionAndSize(nsSubDocumentFrame *aIFrame)
     }
 
     ScreenIntSize size = aIFrame->GetSubdocumentSize();
+    mLazySize = size;
 
     baseWindow->SetPositionAndSize(x, y, size.width, size.height, false);
   }
 }
 
+NS_IMETHODIMP
+nsFrameLoader::GetLazyWidth(uint32_t* aLazyWidth)
+{
+  *aLazyWidth = mLazySize.width;
+
+  nsIFrame* frame = GetPrimaryFrameOfOwningContent();
+  if (frame) {
+    *aLazyWidth = frame->PresContext()->DevPixelsToIntCSSPixels(*aLazyWidth);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFrameLoader::GetLazyHeight(uint32_t* aLazyHeight)
+{
+  *aLazyHeight = mLazySize.height;
+
+  nsIFrame* frame = GetPrimaryFrameOfOwningContent();
+  if (frame) {
+    *aLazyHeight = frame->PresContext()->DevPixelsToIntCSSPixels(*aLazyHeight);
+  }
+
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsFrameLoader::GetEventMode(uint32_t* aEventMode)
 {

dom/base/nsFrameLoader.h

@@ -375,6 +375,9 @@ private:
   // forwards some input events to out-of-process content.
   uint32_t mEventMode;
 
+  // Holds the last known size of the frame.
+  mozilla::ScreenIntSize mLazySize;
+
   bool mIsPrerendered : 1;
   bool mDepthTooGreat : 1;
   bool mIsTopLevelContent : 1;

dom/base/nsIFrameLoader.idl

@@ -208,6 +208,21 @@ interface nsIFrameLoader : nsISupports
    */
   readonly attribute boolean ownerIsWidget;
 
+  /**
+   * The last known width of the frame. Reading this property will not trigger
+   * a reflow, and therefore may not reflect the current state of things. It
+   * should only be used in asynchronous APIs where values are not guaranteed
+   * to be up-to-date when received.
+   */
+  readonly attribute unsigned long lazyWidth;
+
+  /**
+   * The last known height of the frame. Reading this property will not trigger
+   * a reflow, and therefore may not reflect the current state of things. It
+   * should only be used in asynchronous APIs where values are not guaranteed
+   * to be up-to-date when received.
+   */
+  readonly attribute unsigned long lazyHeight;
 };
 
 %{C++