Fix crash in network service webui code when the source gives an empty string.

This is handled correctly by the old webui case.

BUG: 778842
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_mojo
Change-Id: I39013667b9038e9687b418905e56e93868017b24
Reviewed-on: https://chromium-review.googlesource.com/781419Reviewed-by: Yuzhu Shen <yzshen@chromium.org>
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#518275}

content/browser/webui/web_ui_url_loader_factory.cc

@@ -100,15 +100,15 @@ void ReadData(scoped_refptr<ResourceResponse> headers,
   MojoResult result = data_pipe.producer_handle->BeginWriteData(
       &buffer, &num_bytes, MOJO_WRITE_DATA_FLAG_NONE);
   CHECK_EQ(result, MOJO_RESULT_OK);
-  CHECK_EQ(num_bytes, output_size);
+  CHECK_GE(num_bytes, output_size);
 
   if (gzipped) {
-    base::StringPiece output(static_cast<char*>(buffer), num_bytes);
+    base::StringPiece output(static_cast<char*>(buffer), output_size);
     CHECK(compression::GzipUncompress(input, output));
   } else {
     memcpy(buffer, bytes->front(), output_size);
   }
-  result = data_pipe.producer_handle->EndWriteData(num_bytes);
+  result = data_pipe.producer_handle->EndWriteData(output_size);
   CHECK_EQ(result, MOJO_RESULT_OK);
 
   client->OnStartLoadingResponseBody(std::move(data_pipe.consumer_handle));

testing/buildbot/filters/mojo.fyi.network_browser_tests.filter

@@ -435,7 +435,10 @@
 -ProfileBrowserTest.SendHPKPReport
 -ProfileBrowserTest.SendHPKPReportServerHangs
 -ReferrerPolicyTest.ContextMenuOrigin
+-ReferrerPolicyTest.ContextMenuRedirect
 -ReferrerPolicyTest.History
+-ReferrerPolicyTest.HttpsContextMenuOrigin
+-ReferrerPolicyTest.HttpsContextMenuRedirect
 -ReferrerPolicyTest.HttpLeftClickHTTPRedirectToHTTPSSameOrigin
 -ReferrerPolicyTest.HttpLeftClickHTTPRedirectToHTTPSameOrigin
 -ReferrerPolicyTest.HttpLeftClickHTTPRedirectToHTTPStrictOrigin
@@ -497,10 +500,6 @@
 # crbug.com/778814 Null NavigationData is given to NavigationURLLoaderDelegate::OnResponseStarted() as parameter.
 -ChromeResourceDispatcherHostDelegateBrowserTest.NavigationDataProcessed
 
-# crbug.com/778842 CHECK_EQ(num_bytes, output_size) failed in ReadData() at web_ui_url_loader_factory.cc.
--DevToolsReattachAfterCrashTest.TestReattachAfterCrashOnNetwork
--DevToolsReattachAfterCrashTest.TestReattachAfterCrashOnTimeline
-
 # crbug.com/778846 DCHECK() failed at URLDataManagerBackend::CheckURLIsValid().
 # Note: these may flake pass, but don't enable them.
 -CrSettingsPeoplePageTest.All
@@ -516,11 +515,6 @@
 -HotwordInstallerBrowserTest.AbortInstallOnShutdown
 -SpellingMenuObserverTest.SuggestionsForceTopSeparator
 
-# crbug.com/779236 DCHECK(!params->url.is_empty()) fails at chrome::Navigate().
--ReferrerPolicyTest.ContextMenuRedirect
--ReferrerPolicyTest.HttpsContextMenuOrigin
--ReferrerPolicyTest.HttpsContextMenuRedirect
-
 # http://crbug.com/783990
 # Add support for http auth.
 -LoginPromptBrowserTest.AllowCrossdomainPromptForSubframes