Avoid infinite loops in SpellcheckService::OnCustomDictionaryChanged.

r567099 introduced a bug, where the loop in
SpellcheckService::OnCustomDictionaryChanged could spin forever
without calling RenderProcessHost::iterator::Advance.  This CL fixes
this.

Bug: 854540
Change-Id: I6a1829a3595a1414ceb75b125b54a4576b3c02a6
Reviewed-on: https://chromium-review.googlesource.com/1108540Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Łukasz Anforowicz <lukasza@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569489}

chrome/browser/spellchecker/spellcheck_service.cc

@@ -283,14 +283,14 @@ void SpellcheckService::OnCustomDictionaryChanged(
     const SpellcheckCustomDictionary::Change& change) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
-  auto process_hosts(content::RenderProcessHost::AllHostsIterator());
-
   const std::vector<std::string> additions(change.to_add().begin(),
                                            change.to_add().end());
   const std::vector<std::string> deletions(change.to_remove().begin(),
                                            change.to_remove().end());
-  while (!process_hosts.IsAtEnd()) {
-    content::RenderProcessHost* process = process_hosts.GetCurrentValue();
+  for (content::RenderProcessHost::iterator it(
+           content::RenderProcessHost::AllHostsIterator());
+       !it.IsAtEnd(); it.Advance()) {
+    content::RenderProcessHost* process = it.GetCurrentValue();
     if (!process->IsInitializedAndNotDead())
       continue;
 
@@ -302,7 +302,6 @@ void SpellcheckService::OnCustomDictionaryChanged(
                                   renderer_identity.instance()),
         &spellchecker);
     spellchecker->CustomDictionaryChanged(additions, deletions);
-    process_hosts.Advance();
   }
 }
 

chrome/browser/spellchecker/spellcheck_service_browsertest.cc

@@ -33,6 +33,7 @@
 #include "components/spellcheck/common/spellcheck_common.h"
 #include "components/spellcheck/common/spellcheck_result.h"
 #include "components/user_prefs/user_prefs.h"
+#include "content/public/test/browser_test_utils.h"
 #include "content/public/test/mock_render_process_host.h"
 #include "content/public/test/test_utils.h"
 #include "mojo/public/cpp/bindings/binding.h"
@@ -386,6 +387,28 @@ IN_PROC_BROWSER_TEST_F(SpellcheckServiceBrowserTest, CustomDictionaryChanged) {
   EXPECT_TRUE(GetCustomDictionaryChangedState());
 }
 
+// Regression test for https://crbug.com/854540.
+IN_PROC_BROWSER_TEST_F(SpellcheckServiceBrowserTest,
+                       CustomDictionaryChangedAfterRendererCrash) {
+  InitSpellcheck(true, "en-US", "");
+  EXPECT_TRUE(GetEnableSpellcheckState());
+
+  // Kill the renderer process.
+  content::RenderProcessHost* process = browser()
+                                            ->tab_strip_model()
+                                            ->GetActiveWebContents()
+                                            ->GetMainFrame()
+                                            ->GetProcess();
+  content::RenderProcessHostWatcher crash_observer(
+      process, content::RenderProcessHostWatcher::WATCH_FOR_PROCESS_EXIT);
+  EXPECT_TRUE(process->Shutdown(0));
+  crash_observer.Wait();
+
+  // Change the custom dictionary - the test passes if there were no crashes or
+  // hangs.
+  ChangeCustomDictionary();
+}
+
 // Starting with only a single-language spellcheck setting, the host should
 // initialize the renderer's spellcheck system, and the same if the renderer
 // explicity requests the spellcheck dictionaries.