Unify ranges to use snake_case

For consistency with the API [1], to make it less confusing.

[1] https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#comment-range

Change-Id: I1a77af83bdeadfce4baa629a500a6ea04762e856
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js
index 5e4a3fd..814c7268 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js
@@ -45,11 +45,6 @@
     return !!(diff.binary && (isA || isB));
   }
 
-  /** @typedef {{startLine: number, startChar: number,
-   *             endLine: number, endChar: number}} */
-  Gerrit.Range;
-
-
   /**
    * Compare two ranges. Either argument may be falsy, but will only return
    * true if both are falsy or if neither are falsy and have the same position
@@ -62,10 +57,10 @@
   function rangesEqual(a, b) {
     if (!a && !b) { return true; }
     if (!a || !b) { return false; }
-    return a.startLine === b.startLine &&
-        a.startChar === b.startChar &&
-        a.endLine === b.endLine &&
-        a.endChar === b.endChar;
+    return a.start_line === b.start_line &&
+        a.start_character === b.start_character &&
+        a.end_line === b.end_line &&
+        a.end_character === b.end_character;
   }
 
   /**
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.html b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.html
index c7ee1c2..423bdc6 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.html
@@ -966,10 +966,10 @@
 
       // Try to fetch a thread with a different range.
       range = {
-        startLine: 1,
-        startChar: 1,
-        endLine: 1,
-        endChar: 3,
+        start_line: 1,
+        start_character: 1,
+        end_line: 1,
+        end_character: 3,
       };
 
       assert.isOk(element._getOrCreateThread(