[Live Caption] Fix a crash caused by the SODAInstaller notifying an

observer.

This CL does two things:
1. Do not notify SODAInstallerObservers when the component has not been
updated. The crash was initiated when the component updater sent a
status update saying that the SODA component was up-to-date, which
occurred while SODA was running and not when it was installing. These
up-to-date messages should not be relayed to the SODAInstallerObservers.

2. Remove the CaptionsHandler from the SODAInstaller observer list when
the CaptionsHandler is destructed. The crash occurred because the
CaptionsHandler had not properly removed itself as an observer. Before
this CL, the CaptionsHandler removed itself when javascript was
disallowed, which was assumed to occur when the CaptionsHandler was
destructed. On testing, it turns out that this is not the case, so this
CL ensures that the CaptionsHandler is removed as an observer on
destruction.

Bug: 1055150, 1155625
Change-Id: Icb2073a1380f1d1cefc25690d84aa840804ff29c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2575005Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Commit-Queue: Abigail Klein <abigailbklein@google.com>
Cr-Commit-Position: refs/heads/master@{#834027}

chrome/browser/accessibility/soda_installer_impl.cc

@@ -108,13 +108,13 @@ void SODAInstallerImpl::OnEvent(Events event, const std::string& id) {
       }
     } break;
     case Events::COMPONENT_UPDATED:
-    case Events::COMPONENT_NOT_UPDATED:
       NotifyOnSODAInstalled();
       break;
     case Events::COMPONENT_UPDATE_ERROR:
       NotifyOnSODAError();
       break;
     case Events::COMPONENT_CHECKING_FOR_UPDATES:
+    case Events::COMPONENT_NOT_UPDATED:
       // Do nothing.
       break;
   }

chrome/browser/ui/webui/settings/captions_handler.cc

@@ -23,7 +23,9 @@ namespace settings {
 
 CaptionsHandler::CaptionsHandler(PrefService* prefs) : prefs_(prefs) {}
 
-CaptionsHandler::~CaptionsHandler() = default;
+CaptionsHandler::~CaptionsHandler() {
+  speech::SODAInstaller::GetInstance()->RemoveObserver(this);
+}
 
 void CaptionsHandler::RegisterMessages() {
   web_ui()->RegisterMessageCallback(