DevTools: [Search] do not search inside binary files.

This patch skips binary UISourceCodes so that we don't search in them.

BUG=585383
R=dgozman

Review-Url: https://codereview.chromium.org/2564733002
Cr-Commit-Position: refs/heads/master@{#437467}

front_end/sources/SourcesSearchScope.js

@@ -139,6 +139,8 @@ Sources.SourcesSearchScope = class {
     var uiSourceCodes = project.uiSourceCodes();
     for (var i = 0; i < uiSourceCodes.length; ++i) {
       var uiSourceCode = uiSourceCodes[i];
+      if (!uiSourceCode.contentType().isTextType())
+        continue;
       var binding = Persistence.persistence.binding(uiSourceCode);
       if (binding && binding.network === uiSourceCode)
         continue;