Fixed javascript_dialog_manager to compile when extensions are disabled.

chrome/browser/ui/app_modal_dialogs/javascript_dialog_manager.cc

Index: chrome/browser/ui/app_modal_dialogs/javascript_dialog_manager.cc
diff --git a/chrome/browser/ui/app_modal_dialogs/javascript_dialog_manager.cc b/chrome/browser/ui/app_modal_dialogs/javascript_dialog_manager.cc
index 417a2898d0d5c5ca24a6a3f7a3de5ec48c670b12..cc006d907b9c6d351a68ce690f11156a3252db6f 100644
--- a/chrome/browser/ui/app_modal_dialogs/javascript_dialog_manager.cc
+++ b/chrome/browser/ui/app_modal_dialogs/javascript_dialog_manager.cc
@@ -31,16 +31,14 @@ using extensions::Extension;
 
 namespace {
 
+#if defined(ENABLE_EXTENSIONS)
 // Returns the ProcessManager for the browser context from |web_contents|.
 extensions::ProcessManager* GetExtensionsProcessManager(
     WebContents* web_contents) {
-#if defined(ENABLE_EXTENSIONS)
   return extensions::ExtensionSystem::Get(
       web_contents->GetBrowserContext())->process_manager();
-#else
-  return NULL;
-#endif  // defined(ENABLE_EXTENSIONS)
 }
+#endif  // ENABLE_EXTENSIONS
 
 // Returns the extension associated with |web_contents| or NULL if there is no
 // associated extension (or extensions are not supported).
@@ -50,7 +48,7 @@ const Extension* GetExtensionForWebContents(WebContents* web_contents) {
   return pm->GetExtensionForRenderViewHost(web_contents->GetRenderViewHost());
 #else
   return NULL;
-#endif  // defined(ENABLE_EXTENSIONS)
+#endif  // ENABLE_EXTENSIONS

[Lei Zhang, 2014/08/22 22:39:50]

nit: I think most people do // defined(FOO)

[David Yen, 2014/08/22 23:03:58]

Done.

 }
 
 // Keeps an |extension| from shutting down its lazy background page. If an
@@ -58,22 +56,26 @@ const Extension* GetExtensionForWebContents(WebContents* web_contents) {
 // dialog closes.
 void IncrementLazyKeepaliveCount(const Extension* extension,
                                  WebContents* web_contents) {
+#if defined(ENABLE_EXTENSIONS)

[msw, 2014/08/22 22:36:10]

I'm actually not sure what build errors you'd see by omitting these guards.
Further, these shoudn't even be called if |GetExtensionForWebContents| is
returning NULL and blocking the calls below. What am I missing?

[David Yen, 2014/08/22 23:05:52]

Even though technically it can never be called, there is a linker error on
pm->IncrementalLazyKeepaliveCount() and pm->DecrementLazyKeepaliveCount().

   DCHECK(extension);
   DCHECK(web_contents);
   extensions::ProcessManager* pm = GetExtensionsProcessManager(web_contents);
   if (pm)
     pm->IncrementLazyKeepaliveCount(extension);
+#endif  // ENABLE_EXTENSIONS
 }
 
 // Allows an |extension| to shut down its lazy background page after a dialog
 // closes (if nothing else is keeping it open).
 void DecrementLazyKeepaliveCount(const Extension* extension,
                                  WebContents* web_contents) {
+#if defined(ENABLE_EXTENSIONS)
   DCHECK(extension);
   DCHECK(web_contents);
   extensions::ProcessManager* pm = GetExtensionsProcessManager(web_contents);
   if (pm)
     pm->DecrementLazyKeepaliveCount(extension);
+#endif  // ENABLE_EXTENSIONS
 }
 
 class ChromeJavaScriptDialogManager : public JavaScriptDialogManager {