Add filtering by priority in the Network filter area.

third_party/WebKit/Source/devtools/front_end/network/FilterSuggestionBuilder.js

Index: third_party/WebKit/Source/devtools/front_end/network/FilterSuggestionBuilder.js
diff --git a/third_party/WebKit/Source/devtools/front_end/network/FilterSuggestionBuilder.js b/third_party/WebKit/Source/devtools/front_end/network/FilterSuggestionBuilder.js
index a3ea2f88fbe51b00dfcfab29793ec9a8047c696e..a3f768ced068784d929f3c979dfa6e2e268a9435 100644
--- a/third_party/WebKit/Source/devtools/front_end/network/FilterSuggestionBuilder.js
+++ b/third_party/WebKit/Source/devtools/front_end/network/FilterSuggestionBuilder.js
@@ -80,10 +80,19 @@ Network.FilterSuggestionBuilder = class {
    */
   _values(key) {
     var result = this._valueLists[key];
+    var priorityMap;
+
     if (!result)
       return [];
 
-    result.sort();
+    if (key === 'priority') {

[allada, 2016/12/17 01:20:20]

nit: if (key === Network.NetworkLogView.FilterType.Priority)

+      priorityMap = Network.NetworkDataGridNode.symbolicToNumericPriority;

[allada, 2016/12/17 01:20:20]

If we change in the other file to send over the uiString, we could then work
with the uiStrings instead of the enums. eg:

var resultSet = new Set(result);
result = [];
var numericToPriorityMap =
Network.NetworkDataGridNode.symbolicToNumericMap().inverse();
var sortedNumericPriorities = numericToPriorityMap.keysArray().sortNumbers();
var sortedPriorities = sortedNumericPriorities.map(value =>
numericToPriorityMap.get(value));

for (var value of sortedPriorities) {
    var uiPriority = resultSet.get(value);
    if (!uiPriority)
        continue;
    result.push(uiPriority);
}
return result;

[Oleksii Kadurin, 2016/12/19 22:02:55]

What is the point in creating Set here? Double check for uniqueness?
inverse function returns MultyMap, every value of which has type of Set. 
So in order to get a string value by a key it's needed to invoke it like
"inversedMap.get(key).next().value". 
As for me it looks not good. If it's ok please let me know.
To avoid such syntax I modified 'inverse' function a little. Not it can return
ordinary map.
I couldn't find such an API. Hence I modified the piece of code you provided.

+      result = result.sort((a, b) => priorityMap.get(b) - priorityMap.get(a));
+      result = result.map(priority => Components.uiLabelForPriority(priority));
+    } else {
+      result.sort();
+    }
+
     return result;
   }