Remaining tricky bits to build webkit_unit_tests with -Wimplicit-fallthrough.

For Range objects where min or max value can't be queried (due to
the node being detached), we currently fall through to the splitter
code which then returns a value of 50 for the range. This Cl makes it
explicit that this behavior is intended.

This CL was uploaded by git cl split.

R=dmazzoni@chromium.org

Bug: 177475
Change-Id: Ife0beab1bc377ca17998601934f4dd38c2349159
Reviewed-on: https://chromium-review.googlesource.com/890074Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533014}

third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp

@@ -1583,6 +1583,7 @@ bool AXNodeObject::ValueForRange(float* out_value) const {
         *out_value = (min_value + max_value) / 2.0f;
         return true;
       }
+      FALLTHROUGH;
     }
     case kSplitterRole: {
       *out_value = 50.0f;