With the following patch I can show partial results by ignoring the invalid results:

diff --git a/appengine/test_results/static-dashboards/loader.js b/appengine/test_results/static-dashboards/loader.js
index fa7f9d0..df97913 100644
--- a/appengine/test_results/static-dashboards/loader.js
+++ b/appengine/test_results/static-dashboards/loader.js
@@ -147,6 +147,7 @@ loader.Loader.prototype = {
         var resultsFileLocation = pathToBuilderResultsFile(builder) + resultsFilename;
         loader.request(resultsFileLocation,
                 partial(function(loader, builder, xhr) {
+                    console.log(resultsFileLocation);
                     loader._handleResultsFileLoaded(builder, xhr.responseText);
                 }, this, builder),
                 partial(function(loader, builder, xhr) {
@@ -176,7 +177,14 @@ loader.Loader.prototype = {
     },
     _processResultsJSONData: function(builder, fileData)
     {
-        var builds = JSON.parse(fileData);
+        try {
+            var builds = JSON.parse(fileData);
+        } catch (e) {
+            console.log(builder);
+            console.log(fileData.substring(0, 100));
+            console.log(e);
+            return;
+        }
 
         if (builder.builderName == 'version' || builder.builderName == 'failure_map')
              return;

+nishanths who just made changes to this

Issue 632485 has been merged into this issue.

Looking into this. Is this happening only for the URL listed above? (http://test-results.appspot.com/testfile?builder=WebKit%20Linux%20(dbg)&master=chromium.webkit&testtype=webkit_tests&name=results-small.json)

Assigning to nishanths@ since he's looking into it. Feel free to bounce back to me (or the current trooper) if it turns out unrelated to your change.

This happens on multiple URLs. You can open flakiness_dashboard.html with the patch in #1 applied to see the URLs containing bad results.

The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra.git/+/0290e4c044aa08a8729c1a84960d115f57be04e8

commit 0290e4c044aa08a8729c1a84960d115f57be04e8
Author: nishanths <nishanths@google.com>
Date: Thu Jul 28 23:09:22 2016

test-results: stop routing to new Go module

BUG= 632484 

Review-Url: https://codereview.chromium.org/2192003002

[delete] https://crrev.com/8089c423fec7d2fcf3cc472de776c42cd307eefc/go/src/infra/appengine/test-results/dispatch.yaml

Rolled back to the old Python module. 

http://test-results.appspot.com/testfile?builder=WebKit%20Linux%20(dbg)&master=chromium.webkit&testtype=webkit_tests&name=results-small.json now returns valid JSON. 

Flakiness dashboard is back up too: http://test-results.appspot.com/dashboards/flakiness_dashboard.html. 

This occurs again. Console log:

VM213:1 Uncaught SyntaxError: Unexpected token s in JSON at position 3000239_processResultsJSONData @ loader.js:179_handleResultsFileLoaded @ loader.js:161(anonymous function) @ loader.js:150(anonymous function) @ base.js:45xhr.onreadystatechange @ loader.js:54
VM214:1 Uncaught SyntaxError: Unexpected token , in JSON at position 1_processResultsJSONData @ loader.js:179_handleResultsFileLoaded @ loader.js:161(anonymous function) @ loader.js:150(anonymous function) @ base.js:45xhr.onreadystatechange @ loader.js:54
VM215:1 Uncaught SyntaxError: Unexpected token , in JSON at position 0_processResultsJSONData @ loader.js:179_handleResultsFileLoaded @ loader.js:161(anonymous function) @ loader.js:150(anonymous function) @ base.js:45xhr.onreadystatechange @ loader.js:54
VM216:1 Uncaught SyntaxError: Unexpected token t in JSON at position 3000000_processResultsJSONData @ loader.js:179_handleResultsFileLoaded @ loader.js:161(anonymous function) @ loader.js:150(anonymous function) @ base.js:45xhr.onreadystatechange @ loader.js:54
VM217:1 Uncaught SyntaxError: Unexpected token [ in JSON at position 3000000_processResultsJSONData @ loader.js:179_handleResultsFileLoaded @ loader.js:161(anonymous function) @ loader.js:150(anonymous function) @ base.js:45xhr.onreadystatechange @ loader.js:54
loader.js:59 GET http://test-results.appspot.com/testfile?builder=WebKit%20Win%20-%20WPTServe&master=chromium.fyi&testtype=webkit_tests&name=results-small.json 404 (Not Found)loader.request @ loader.js:59_loadResultsFileForBuilder @ loader.js:148_loadResultsFiles @ loader.js:130_loadNext @ loader.js:120_loadBuilders @ loader.js:125_loadNext @ loader.js:120load @ loader.js:100(anonymous function) @ flakiness_dashboard.js:1602
VM218:1 Uncaught SyntaxError: Unexpected token , in JSON at position 0_processResultsJSONData @ loader.js:179_handleResultsFileLoaded @ loader.js:161(anonymous function) @ loader.js:150(anonymous function) @ base.js:45xhr.onreadystatechange @ loader.js:54
VM219:1 Uncaught SyntaxError: Unexpected token ] in JSON at position 3000001

Nishanth, I think you rolled out a change yesterday?  Please take a look ASAP.

(And, once resolved, can you also get a bug on file to add monitoring)

Looking into this.

Issue 638967 has been merged into this issue.

We should consider rolling back at this point. :)

Applied the patch from Comment 1 for a temporary fix. 

The dashboard is back up: http://test-results.appspot.com/dashboards/flakiness_dashboard.html. However the failing JSON will not be included in the dashboard statistics.

Looking at a permanent fix now.