Bug 1287728 - part1: explicitly define default value for RestyleResult. r=heycam

After explicitly define default value for RestyleResult, we have a value
starting from 0 now. So, we can drop the explicity numbering.

MozReview-Commit-ID: 1UlpkUT6mAL

--HG--
extra : rebase_source : 441da4a5def8b9c8340cc3048d8dba5ddaae3b87

layout/base/RestyleManager.cpp

@@ -3264,7 +3264,7 @@ ElementRestyler::Restyle(nsRestyleHint aRestyleHint)
   // its descendants, yet RestyleSelf might return different RestyleResult
   // values for the different same-style continuations.  |result| is our
   // overall decision.
-  RestyleResult result = RestyleResult(0);
+  RestyleResult result = eRestyleResult_None;
   uint32_t swappedStructs = 0;
 
   nsRestyleHint thisRestyleHint = aRestyleHint;
@@ -5194,7 +5194,8 @@ ElementRestyler::RestyleResultToString(RestyleResult aRestyleResult)
       result.AssignLiteral("eRestyleResult_ContinueAndForceDescendants");
       break;
     default:
-      result.AppendPrintf("RestyleResult(%d)", aRestyleResult);
+      MOZ_ASSERT(aRestyleResult == eRestyleResult_None,
+                 "Unexpected RestyleResult");
   }
   return result;
 }

layout/base/RestyleManager.h

@@ -671,9 +671,11 @@ private:
   // These values must be ordered so that later values imply that all
   // the work of the earlier values is also done.
   enum RestyleResult {
+    // default initial value
+    eRestyleResult_None,
 
     // we left the old style context on the frame; do not restyle children
-    eRestyleResult_Stop = 1,
+    eRestyleResult_Stop,
 
     // we got a new style context on this frame, but we know that children
     // do not depend on the changed values; do not restyle children