Work more on getting things built with -Wimplicit-fallthrough.

This CL was uploaded by git cl split.

R=eae@chromium.org

Bug: 177475
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_layout_ng
Change-Id: I3a861bf5eb39da51b628eafae99d0bff3ebfab39
Reviewed-on: https://chromium-review.googlesource.com/889728Reviewed-by: Christian Biesinger <cbiesinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532255}

third_party/WebKit/Source/core/layout/ng/inline/ng_inline_box_state.cc

@@ -493,7 +493,7 @@ NGInlineLayoutStateStack::ApplyBaselineShift(
             break;
           }
           NOTREACHED();
-        // Fall through.
+          FALLTHROUGH;
         case EVerticalAlign::kBottom:
           if (box->metrics.IsEmpty())
             baseline_shift = -child.metrics.descent;

third_party/WebKit/Source/core/layout/ng/ng_fragmentation_utils.cc

@@ -61,7 +61,7 @@ inline int FragmentainerBreakPrecedence(EBreakBetween break_value) {
   switch (break_value) {
     default:
       NOTREACHED();
-    // fall-through
+      FALLTHROUGH;
     case EBreakBetween::kAuto:
       return 0;
     case EBreakBetween::kAvoidColumn:

third_party/WebKit/Source/core/layout/ng/ng_length_utils.cc

@@ -117,6 +117,7 @@ LayoutUnit ResolveInlineLength(const NGConstraintSpace& constraint_space,
     case kDeviceHeight:
     case kExtendToZoom:
       NOTREACHED() << "These should only be used for viewport definitions";
+      FALLTHROUGH;
     case kMaxSizeNone:
     default:
       NOTREACHED();
@@ -193,6 +194,7 @@ LayoutUnit ResolveBlockLength(const NGConstraintSpace& constraint_space,
     case kDeviceHeight:
     case kExtendToZoom:
       NOTREACHED() << "These should only be used for viewport definitions";
+      FALLTHROUGH;
     case kMaxSizeNone:
     default:
       NOTREACHED();