Don't awake suspended IME extension's background except for onActivate.

For suspended IME extension (e.g. XKB extension), don't awake it by IME
 events except onActivate. The IME extension should be awake by other
events (e.g. runtime.onMessage) from its other pages. This is to save
memory for steady state Chrome OS on which the users don't want any
IME features.

BUG=451627
TEST=Verified on linux_chromeos.

Review URL: https://codereview.chromium.org/884713005

Cr-Commit-Position: refs/heads/master@{#314100}

chrome/browser/extensions/api/input_ime/input_ime_api.cc

@@ -19,6 +19,7 @@
 #include "extensions/browser/extension_function_registry.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/browser/extension_system.h"
+#include "extensions/browser/process_manager.h"
 #include "extensions/common/manifest_handlers/background_info.h"
 #include "ui/base/ime/chromeos/component_extension_ime_manager.h"
 #include "ui/base/ime/chromeos/extension_ime_util.h"
@@ -81,6 +82,27 @@ static void DispatchEventToExtension(const std::string& extension_id,
                                      const std::string& event_name,
                                      scoped_ptr<base::ListValue> args) {
   Profile* profile = ProfileManager::GetActiveUserProfile();
+  if (event_name != input_ime::OnActivate::kEventName) {
+    // For suspended IME extension (e.g. XKB extension), don't awake it by IME
+    // events except onActivate. The IME extension should be awake by other
+    // events (e.g. runtime.onMessage) from its other pages.
+    // This is to save memory for steady state Chrome OS on which the users
+    // don't want any IME features.
+    extensions::ExtensionSystem* extension_system =
+        extensions::ExtensionSystem::Get(profile);
+    if (extension_system) {
+      const extensions::Extension* extension =
+          extension_system->extension_service()->GetExtensionById(
+              extension_id, false /* include_disabled */);
+      extensions::ProcessManager* process_manager =
+          extensions::ProcessManager::Get(profile);
+      if (extensions::BackgroundInfo::HasBackgroundPage(extension) &&
+          !process_manager->GetBackgroundHostForExtension(extension_id)) {
+        return;
+      }
+    }
+  }
+
   scoped_ptr<extensions::Event> event(new extensions::Event(
       event_name, args.Pass()));
   event->restrict_to_browser_context = profile;