Introduce runtime.onSuspendCanceled() event.

chrome/browser/extensions/extension_process_manager.cc

Index: chrome/browser/extensions/extension_process_manager.cc
diff --git a/chrome/browser/extensions/extension_process_manager.cc b/chrome/browser/extensions/extension_process_manager.cc
index ac453d6182d0aec5ae03f332171aeadcec37c91a..0338fc0523a78cf0751cae45352bce416f315311 100644
--- a/chrome/browser/extensions/extension_process_manager.cc
+++ b/chrome/browser/extensions/extension_process_manager.cc
@@ -5,6 +5,7 @@
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
+#include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/string_number_conversions.h"
@@ -112,9 +113,9 @@ struct ExtensionProcessManager::BackgroundPageData {
   int close_sequence_id;
 
   // True if the page responded to the ShouldUnload message and is currently
-  // dispatching the unload event. We use this to ignore any activity
-  // generated during the unload event that would otherwise keep the
-  // extension alive.
+  // dispatching the unload event. During this time any events that arrive will
+  // cancel the unload process and an onSuspendCanceled event will be dispatched
+  // to the page.
   bool is_closing;
 
   // Keeps track of when this page was last unloaded. Used for perf metrics.
@@ -413,17 +414,31 @@ int ExtensionProcessManager::GetLazyKeepaliveCount(const Extension* extension) {
 }
 
 int ExtensionProcessManager::IncrementLazyKeepaliveCount(
-     const Extension* extension) {
+     const Extension* extension, bool cancel_suspend) {
   if (!extension->has_lazy_background_page())
     return 0;
 
   int& count = background_page_data_[extension->id()].lazy_keepalive_count;
-  if (++count == 1)
+  bool& is_closing = background_page_data_[extension->id()].is_closing;
+  if (++count == 1) {
+    if (cancel_suspend && is_closing) {
+      is_closing = false;
+      ExtensionHost* host = GetBackgroundHostForExtension(extension->id());
+      if (host)
+        host->render_view_host()->Send(
+            new ExtensionMsg_CancelUnload(extension->id()));

[benwells, 2012/07/20 10:57:00]

Nit: braces around the if body as there is more than one physical line.

+    }
     OnLazyBackgroundPageActive(extension->id());
+  }
 
   return count;
 }
 
+int ExtensionProcessManager::IncrementLazyKeepaliveCount(
+     const Extension* extension) {
+  return IncrementLazyKeepaliveCount(extension, false);
+}
+
 int ExtensionProcessManager::DecrementLazyKeepaliveCount(
      const Extension* extension) {
   if (!extension->has_lazy_background_page())
@@ -442,6 +457,7 @@ int ExtensionProcessManager::DecrementLazyKeepaliveCount(
 
   return count;
 }
+
 void ExtensionProcessManager::IncrementLazyKeepaliveCountForView(
     RenderViewHost* render_view_host) {
   WebContents* web_contents =
@@ -492,19 +508,24 @@ void ExtensionProcessManager::OnShouldUnloadAck(
 }
 
 void ExtensionProcessManager::OnUnloadAck(const std::string& extension_id) {
+  background_page_data_[extension_id].is_closing = true;
+  int sequence_id = background_page_data_[extension_id].close_sequence_id;
   MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&ExtensionProcessManager::CloseLazyBackgroundPageNow,
-                 weak_ptr_factory_.GetWeakPtr(), extension_id),
+                 weak_ptr_factory_.GetWeakPtr(), extension_id, sequence_id),
       event_page_unloading_time_);
 }
 
 void ExtensionProcessManager::CloseLazyBackgroundPageNow(
-    const std::string& extension_id) {
-  background_page_data_[extension_id].is_closing = true;
+    const std::string& extension_id, int sequence_id) {
   ExtensionHost* host = GetBackgroundHostForExtension(extension_id);
-  if (host)
-    CloseBackgroundHost(host);
+  if (host &&
+      sequence_id == background_page_data_[extension_id].close_sequence_id) {
+    ExtensionHost* host = GetBackgroundHostForExtension(extension_id);
+    if (host)
+      CloseBackgroundHost(host);
+  }
 }
 
 void ExtensionProcessManager::OnNetworkRequestStarted(
@@ -608,7 +629,7 @@ void ExtensionProcessManager::Observe(
         const Extension* extension = GetExtensionForRenderViewHost(
             render_view_host);
         if (extension)
-          IncrementLazyKeepaliveCount(extension);
+          IncrementLazyKeepaliveCount(extension, true);
       }
       break;
     }