Don't force full repaint on size change in style

Source/core/rendering/RenderObject.cpp

Index: Source/core/rendering/RenderObject.cpp
diff --git a/Source/core/rendering/RenderObject.cpp b/Source/core/rendering/RenderObject.cpp
index 08b70dbe070f06f15d77a1cd068d9e6208867696..ee4dc15196e2df3e12ed93f9713bb0a509fd8127 100644
--- a/Source/core/rendering/RenderObject.cpp
+++ b/Source/core/rendering/RenderObject.cpp
@@ -1590,8 +1590,8 @@ const char* RenderObject::invalidationReasonToString(InvalidationReason reason)
     switch (reason) {
     case InvalidationIncremental:
         return "incremental";
-    case InvalidationSelfLayout:
-        return "self layout";
+    case InvalidationFull:
+        return "full";
     case InvalidationBorderFitLines:
         return "border fit lines";
     case InvalidationBorderRadius:
@@ -1641,7 +1641,7 @@ static PassRefPtr<JSONValue> jsonObjectForOldAndNewRects(const LayoutRect& oldRe
     return object.release();
 }
 
-bool RenderObject::invalidatePaintAfterLayoutIfNeeded(const RenderLayerModelObject* paintInvalidationContainer, bool wasSelfLayout,
+bool RenderObject::invalidatePaintAfterLayoutIfNeeded(const RenderLayerModelObject* paintInvalidationContainer, bool shouldDoFullPaintInvalidation,
     const LayoutRect& oldBounds, const LayoutPoint& oldLocation, const LayoutRect* newBoundsPtr, const LayoutPoint* newLocationPtr)
 {
     RenderView* v = view();
@@ -1658,7 +1658,7 @@ bool RenderObject::invalidatePaintAfterLayoutIfNeeded(const RenderLayerModelObje
         "object", this->debugName().ascii(),
         "info", TracedValue::fromJSONValue(jsonObjectForOldAndNewRects(oldBounds, newBounds)));
 
-    InvalidationReason invalidationReason = wasSelfLayout ? InvalidationSelfLayout : InvalidationIncremental;
+    InvalidationReason invalidationReason = shouldDoFullPaintInvalidation ? InvalidationFull : InvalidationIncremental;
 
     // Presumably a background or a border exists if border-fit:lines was specified.
     if (invalidationReason == InvalidationIncremental && style()->borderFit() == BorderFitLines)
@@ -1710,32 +1710,22 @@ bool RenderObject::invalidatePaintAfterLayoutIfNeeded(const RenderLayerModelObje
         return true;
     }
 
-    LayoutUnit deltaLeft = newBounds.x() - oldBounds.x();
-    if (deltaLeft > 0)

[esprehn, 2014/06/20 08:10:50]

Was this code even reachable before? If the locations were different the case
above on line 1694 will set invalidationReason = InvalidationBoundsChange; which
should make us early return above. How could deltaLeft or deltaRight in the old
code ever be different?

[Xianzhu, 2014/06/20 16:57:01]

I think these code have never been reached (perhaps ever, or since
InvalidationBoundsChange was added).

However now I'd like not to change this in this CL. Will include it in another
change fixing 
crbug.com/380472.

-        invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(oldBounds.x(), oldBounds.y(), deltaLeft, oldBounds.height()), invalidationReason);
-    else if (deltaLeft < 0)
-        invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(newBounds.x(), newBounds.y(), -deltaLeft, newBounds.height()), invalidationReason);
+    ASSERT(newBounds.location() == oldBounds.location());
 
-    LayoutUnit deltaRight = newBounds.maxX() - oldBounds.maxX();
-    if (deltaRight > 0)
-        invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(oldBounds.maxX(), newBounds.y(), deltaRight, newBounds.height()), invalidationReason);
-    else if (deltaRight < 0)
-        invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(newBounds.maxX(), oldBounds.y(), -deltaRight, oldBounds.height()), invalidationReason);
+    LayoutUnit deltaWidth = newBounds.width() - oldBounds.width();
+    if (deltaWidth > 0)
+        invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(oldBounds.maxX(), newBounds.y(), deltaWidth, newBounds.height()), invalidationReason);
+    else if (deltaWidth < 0)
+        invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(newBounds.maxX(), oldBounds.y(), -deltaWidth, oldBounds.height()), invalidationReason);
 
-    LayoutUnit deltaTop = newBounds.y() - oldBounds.y();
-    if (deltaTop > 0)
-        invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(oldBounds.x(), oldBounds.y(), oldBounds.width(), deltaTop), invalidationReason);
-    else if (deltaTop < 0)
-        invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(newBounds.x(), newBounds.y(), newBounds.width(), -deltaTop), invalidationReason);
-
-    LayoutUnit deltaBottom = newBounds.maxY() - oldBounds.maxY();
-    if (deltaBottom > 0)
-        invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(newBounds.x(), oldBounds.maxY(), newBounds.width(), deltaBottom), invalidationReason);
-    else if (deltaBottom < 0)
-        invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(oldBounds.x(), newBounds.maxY(), oldBounds.width(), -deltaBottom), invalidationReason);
+    LayoutUnit deltaHeight = newBounds.height() - oldBounds.height();
+    if (deltaHeight > 0)
+        invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(newBounds.x(), oldBounds.maxY(), newBounds.width(), deltaHeight), invalidationReason);
+    else if (deltaHeight < 0)
+        invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(oldBounds.x(), newBounds.maxY(), oldBounds.width(), -deltaHeight), invalidationReason);
 
     // FIXME: This is a limitation of our visual overflow being a single rectangle.
-    if (!style()->boxShadow() && !style()->hasBorderImageOutsets() && !style()->hasOutline())
+    if (!style()->hasBorder() && !style()->boxShadow() && !style()->hasBorderImageOutsets() && !style()->hasOutline())
         return false;
 
     // We didn't move, but we did change size. Invalidate the delta, which will consist of possibly
@@ -1743,8 +1733,8 @@ bool RenderObject::invalidatePaintAfterLayoutIfNeeded(const RenderLayerModelObje
     RenderStyle* outlineStyle = outlineStyleForPaintInvalidation();
     LayoutUnit outlineWidth = outlineStyle->outlineSize();
     LayoutBoxExtent insetShadowExtent = style()->getBoxShadowInsetExtent();
-    LayoutUnit width = absoluteValue(newBounds.width() - oldBounds.width());
-    if (width) {
+    if (deltaWidth) {
+        LayoutUnit width = absoluteValue(deltaWidth);
         LayoutUnit shadowLeft;
         LayoutUnit shadowRight;
         style()->getBoxShadowHorizontalExtent(shadowLeft, shadowRight);
@@ -1764,8 +1754,8 @@ bool RenderObject::invalidatePaintAfterLayoutIfNeeded(const RenderLayerModelObje
             invalidatePaintUsingContainer(paintInvalidationContainer, pixelSnappedIntRect(rightRect), invalidationReason);
         }
     }
-    LayoutUnit height = absoluteValue(newBounds.height() - oldBounds.height());
-    if (height) {
+    if (deltaHeight) {
+        LayoutUnit height = absoluteValue(deltaHeight);
         LayoutUnit shadowTop;
         LayoutUnit shadowBottom;
         style()->getBoxShadowVerticalExtent(shadowTop, shadowBottom);