Bug 1569701 Part 1 - Make BlockReflowInput::mConsumedBSize a constant, and delete it assessor method. r=dbaron

We always pass consumed block-size into BlockReflowInput's constructor
in nsBlockFrame::Reflow(). By making mConsumedBSize a constant, its
assessor method becomes redundant.

Update the documentation to reflect the reality that ConsumedBSize()
accumulates content block-size from all previous *continuations*, which
was done in Bug 1506293 Part 2.

Differential Revision: https://phabricator.services.mozilla.com/D41906

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

layout/generic/BlockReflowInput.cpp

@@ -43,6 +43,9 @@ BlockReflowInput::BlockReflowInput(const ReflowInput& aReflowInput,
       mLineNumber(0),
       mFloatBreakType(StyleClear::None),
       mConsumedBSize(aConsumedBSize) {
+  NS_ASSERTION(mConsumedBSize != NS_UNCONSTRAINEDSIZE,
+               "The consumed block-size should be constrained!");
+
   WritingMode wm = aReflowInput.GetWritingMode();
   mFlags.mIsFirstInflow = !aFrame->GetPrevInFlow();
   mFlags.mIsOverflowContainer = IS_TRUE_OVERFLOW_CONTAINER(aFrame);
@@ -137,14 +140,6 @@ BlockReflowInput::BlockReflowInput(const ReflowInput& aReflowInput,
   mMinLineHeight = aReflowInput.CalcLineHeight();
 }
 
-nscoord BlockReflowInput::ConsumedBSize() {
-  if (mConsumedBSize == NS_UNCONSTRAINEDSIZE) {
-    mConsumedBSize = mBlock->ConsumedBSize(mReflowInput.GetWritingMode());
-  }
-
-  return mConsumedBSize;
-}
-
 void BlockReflowInput::ComputeReplacedBlockOffsetsForFloats(
     nsIFrame* aFrame, const LogicalRect& aFloatAvailableSpace,
     nscoord& aIStartResult, nscoord& aIEndResult) const {

layout/generic/BlockReflowInput.h

@@ -199,12 +199,6 @@ class BlockReflowInput {
    */
   const mozilla::LogicalMargin& BorderPadding() const { return mBorderPadding; }
 
-  /**
-   * Retrieve the block-axis content size "consumed" by any prev-in-flows.
-   * @note the value is cached so subsequent calls will return the same value
-   */
-  nscoord ConsumedBSize();
-
   // Reconstruct the previous block-end margin that goes before |aLine|.
   void ReconstructMarginBefore(nsLineList::iterator aLine);
 
@@ -384,9 +378,9 @@ class BlockReflowInput {
 
   StyleClear mFloatBreakType;
 
-  // The amount of computed block-direction size "consumed" by
-  // previous-in-flows.
-  nscoord mConsumedBSize;
+  // The amount of computed content block-size "consumed" by our previous
+  // continuations.
+  const nscoord mConsumedBSize;
 
   // Cache the current line's BSize if nsBlockFrame::PlaceLine() fails to
   // place the line. When redoing the line, it will be used to query the

layout/generic/nsBlockFrame.cpp

@@ -1779,7 +1779,7 @@ void nsBlockFrame::ComputeFinalSize(const ReflowInput& aReflowInput,
     finalSize.BSize(wm) =
         ComputeFinalBSize(aReflowInput, aState.mReflowStatus,
                           aState.mBCoord + nonCarriedOutBDirMargin,
-                          borderPadding, aState.ConsumedBSize());
+                          borderPadding, aState.mConsumedBSize);
 
     // Don't carry out a block-end margin when our BSize is fixed.
     aMetrics.mCarriedOutBEndMargin.Zero();

layout/generic/nsSplittableFrame.h

@@ -78,10 +78,12 @@ class nsSplittableFrame : public nsFrame {
         mNextContinuation(nullptr) {}
 
   /**
-   * Return the sum of the block-axis content size of our prev-in-flows.
+   * Return the sum of the block-axis content size of our previous
+   * continuations.
+   *
    * @param aWM a writing-mode to determine the block-axis
    *
-   * @note (bz) This makes laying out a splittable frame with N in-flows
+   * @note (bz) This makes laying out a splittable frame with N continuations
    *       O(N^2)! So, use this function with caution and minimize the number
    *       of calls to this method.
    */
@@ -90,7 +92,7 @@ class nsSplittableFrame : public nsFrame {
   /**
    * Retrieve the effective computed block size of this frame, which is the
    * computed block size, minus the block size consumed by any previous
-   * in-flows.
+   * continuations.
    */
   nscoord GetEffectiveComputedBSize(
       const ReflowInput& aReflowInput,

layout/reftests/bugs/reftest.list

@@ -1025,7 +1025,7 @@ fuzzy-if(Android,0-11,0-17) fuzzy-if(webrender,0-1,0-10) == 413361-1.html 413361
 == 421436-1a.html 421436-1-ref.html
 == 421436-1b.html 421436-1-ref.html
 fuzzy-if(skiaContent,0-1,0-40) == 421632-1.html 421632-1-ref.html
-!= 421710-1.html about:blank
+asserts(1-1) != 421710-1.html about:blank # Bug 1574046
 fails-if(Android) fuzzy-if(webrender,63-64,1024-1024) fails-if(usesRepeatResampling&&!(webrender&&winWidget)) == 421885-1.xml 421885-1-ref.xml
 == 421955-1.html 421955-1-ref.html
 == 422249-1.html 422249-1-ref.html

layout/reftests/pagination/reftest.list

@@ -35,11 +35,11 @@ fails == border-breaking-004-cols.xhtml border-breaking-002-cols.ref.xhtml
 == content-inserted-009.xhtml content-inserted-002.ref.xhtml
 == dynamic-abspos-overflow-01-cols.xhtml dynamic-abspos-overflow-01-cols.ref.xhtml
 == float-clear-000.html float-clear-000.ref.html
-fails == float-clear-001.html float-clear-000.ref.html
+asserts(4-4) fails == float-clear-001.html float-clear-000.ref.html # Bug 1574046
 == float-clear-002.html float-clear-000.ref.html
 fails == float-clear-003.html float-clear-000.ref.html
 == float-clear-000-print.html float-clear-000-print.ref.html
-== float-clear-001-print.html float-clear-000-print.ref.html
+asserts(1-1) == float-clear-001-print.html float-clear-000-print.ref.html # Bug 1574046
 == float-clear-002-print.html float-clear-000-print.ref.html
 == float-clear-003-print.html float-clear-000-print.ref.html
 fails == float-continuations-000.html float-continuations-000.ref.html