Bug 1174003 part 4: [css-flexbox] Remove IsMainAxisHorizontal() check from DoFlexLayout(). r=mats

This patch doesn't affect behavior.  It just replaces some (correct) physical-axis-dependent code with equivalent logical-axis-dependent code.

MozReview-Commit-ID: 27QJU2cFWh

--HG--
extra : rebase_source : 856e90428468aac0d93854a0bc20e78c2dcb8c57

layout/generic/nsFlexContainerFrame.cpp

@@ -4520,10 +4520,10 @@ nsFlexContainerFrame::DoFlexLayout(nsPresContext*           aPresContext,
                                      item->Frame(), availSize);
         if (!sizeOverride) {
           // Directly override the computed main-size, by tweaking reflow state:
-          if (aAxisTracker.IsMainAxisHorizontal()) {
-            childReflowInput.SetComputedWidth(item->GetMainSize());
+          if (item->IsInlineAxisMainAxis()) {
+            childReflowInput.SetComputedISize(item->GetMainSize());
           } else {
-            childReflowInput.SetComputedHeight(item->GetMainSize());
+            childReflowInput.SetComputedBSize(item->GetMainSize());
           }
         }