Backed out changeset 4916ccff311d (bug 1135907) for crashtest failures

layout/base/nsLayoutUtils.cpp

@@ -825,37 +825,6 @@ ApplyRectMultiplier(nsRect aRect, float aMultiplier)
   return nsRect(ceil(newX), ceil(newY), floor(newWidth), floor(newHeight));
 }
 
-// Return the maximum displayport size, based on the LayerManager's maximum
-// supported texture size. The result is in app units.
-static nscoord
-GetMaxDisplayPortSize(nsIContent* aContent)
-{
-  MOZ_ASSERT(!gfxPrefs::LayersTilesEnabled(), "Do not clamp displayports if tiling is enabled");
-
-  nsIFrame* frame = aContent->GetPrimaryFrame();
-  if (!frame) {
-    return nscoord_MAX;
-  }
-
-  // Grab the pres context before calling GetDisplayRootFrame, since the two
-  // may have different contexts and therefore different resolutions.
-  nsPresContext* presContext = frame->PresContext();
-
-  frame = nsLayoutUtils::GetDisplayRootFrame(frame);
-
-  nsIWidget* widget = frame->GetNearestWidget();
-  if (!widget) {
-    return nscoord_MAX;
-  }
-  LayerManager* lm = widget->GetLayerManager();
-  if (!lm) {
-    return nscoord_MAX;
-  }
-
-  uint32_t maxSizeInDevPixels = lm->GetMaxTextureSize();
-  return presContext->DevPixelsToAppUnits(maxSizeInDevPixels);
-}
-
 static nsRect
 GetDisplayPortFromRectData(nsIContent* aContent,
                            DisplayPortPropertyData* aRectData,
@@ -927,27 +896,27 @@ GetDisplayPortFromMarginsData(nsIContent* aContent,
     gfxSize localRes = presContext->PresShell()->GetResolution();
     parentRes.scale /= localRes.width;
   }
-
   ScreenRect screenRect = LayoutDeviceRect::FromAppUnits(base, auPerDevPixel)
                         * parentRes;
 
-  if (gfxPrefs::LayersTilesEnabled()) {
-    // Note on the correctness of applying the alignment in Screen space:
-    //   The correct space to apply the alignment in would be Layer space, but
-    //   we don't necessarily know the scale to convert to Layer space at this
-    //   point because Layout may not yet have chosen the resolution at which to
-    //   render (it chooses that in FrameLayerBuilder, but this can be called
-    //   during display list building). Therefore, we perform the alignment in
-    //   Screen space, which basically assumes that Layout chose to render at
-    //   screen resolution; since this is what Layout does most of the time,
-    //   this is a good approximation. A proper solution would involve moving
-    //   the choosing of the resolution to display-list building time.
-    int alignmentX = gfxPlatform::GetPlatform()->GetTileWidth();
-    int alignmentY = gfxPlatform::GetPlatform()->GetTileHeight();
+  // Expand the rect by the margins
+  screenRect.Inflate(aMarginsData->mMargins);
 
-    // Expand the rect by the margins
-    screenRect.Inflate(aMarginsData->mMargins);
+  int alignmentX = gfxPlatform::GetPlatform()->GetTileWidth();
+  int alignmentY = gfxPlatform::GetPlatform()->GetTileHeight();
 
+  // And then align it to the requested alignment.
+  // Note on the correctness of applying the alignment in Screen space:
+  //   The correct space to apply the alignment in would be Layer space, but
+  //   we don't necessarily know the scale to convert to Layer space at this
+  //   point because Layout may not yet have chosen the resolution at which to
+  //   render (it chooses that in FrameLayerBuilder, but this can be called
+  //   during display list building). Therefore, we perform the alignment in
+  //   Screen space, which basically assumes that Layout chose to render at
+  //   screen resolution; since this is what Layout does most of the time,
+  //   this is a good approximation. A proper solution would involve moving the
+  //   choosing of the resolution to display-list building time.
+  if (gfxPrefs::LayersTilesEnabled() && (alignmentX > 0 && alignmentY > 0)) {
     // Inflate the rectangle by 1 so that we always push to the next tile
     // boundary. This is desirable to stop from having a rectangle with a
     // moving origin occasionally being smaller when it coincidentally lines
@@ -972,37 +941,9 @@ GetDisplayPortFromMarginsData(nsIContent* aContent,
     float h = alignmentY * ceil(screenRect.YMost() / alignmentY) - y;
     screenRect = ScreenRect(x, y, w, h);
     screenRect -= scrollPosScreen;
-  } else {
-    nscoord maxSizeInAppUnits = GetMaxDisplayPortSize(aContent);
-    if (maxSizeInAppUnits == nscoord_MAX) {
-      // Pick a safe maximum displayport size for sanity purposes. This is the
-      // lowest maximum texture size on tileless-platforms (Windows, D3D10).
-      maxSizeInAppUnits = presContext->DevPixelsToAppUnits(8192);
-    }
-
-    // Find the maximum size in screen pixels.
-    int32_t maxSizeInDevPixels = presContext->AppUnitsToDevPixels(maxSizeInAppUnits);
-    int32_t maxSizeInScreenPixels = floor(double(maxSizeInDevPixels) * res.scale);
-
-    // For each axis, inflate the margins up to the maximum size.
-    const ScreenMargin& margins = aMarginsData->mMargins;
-    if (screenRect.height < maxSizeInScreenPixels) {
-      int32_t budget = maxSizeInScreenPixels - screenRect.height;
-
-      int32_t top = std::min(int32_t(margins.top), budget);
-      screenRect.y -= top;
-      screenRect.height += top + std::min(int32_t(margins.bottom), budget - top);
-    }
-    if (screenRect.width < maxSizeInScreenPixels) {
-      int32_t budget = maxSizeInScreenPixels - screenRect.width;
-
-      int32_t left = std::min(int32_t(margins.left), budget);
-      screenRect.x -= left;
-      screenRect.width += left + std::min(int32_t(margins.right), budget - left);
-    }
   }
 
-  // Convert the aligned rect back into app units.
+  // Convert the aligned rect back into app units
   nsRect result = LayoutDeviceRect::ToAppUnits(screenRect / res, auPerDevPixel);
 
   // Expand it for the low-res buffer if needed
@@ -1046,23 +987,11 @@ GetDisplayPortImpl(nsIContent* aContent, nsRect *aResult, float aMultiplier)
   NS_ASSERTION((rectData == nullptr) != (marginsData == nullptr),
                "Only one of rectData or marginsData should be set!");
 
-  nsRect result;
   if (rectData) {
-    result = GetDisplayPortFromRectData(aContent, rectData, aMultiplier);
+    *aResult = GetDisplayPortFromRectData(aContent, rectData, aMultiplier);
   } else {
-    result = GetDisplayPortFromMarginsData(aContent, marginsData, aMultiplier);
+    *aResult = GetDisplayPortFromMarginsData(aContent, marginsData, aMultiplier);
   }
-
-  if (!gfxPrefs::LayersTilesEnabled()) {
-    // Either we should have gotten a valid rect directly from the displayport
-    // base, or we should have computed a valid rect from the margins.
-    NS_ASSERTION(result.width <= GetMaxDisplayPortSize(aContent),
-                 "Displayport must be a valid texture size");
-    NS_ASSERTION(result.height <= GetMaxDisplayPortSize(aContent),
-                 "Displayport must be a valid texture size");
-  }
-
-  *aResult = result;
   return true;
 }