Keep NaCl plugins used in app background pages alive when active.

chrome/browser/nacl_host/nacl_process_host.cc

Index: chrome/browser/nacl_host/nacl_process_host.cc
diff --git a/chrome/browser/nacl_host/nacl_process_host.cc b/chrome/browser/nacl_host/nacl_process_host.cc
index 530ebbb50318b7ab873e46560581e670801946ad..395be23cc3bcf1d75fc7e859098e788d351d70cc 100644
--- a/chrome/browser/nacl_host/nacl_process_host.cc
+++ b/chrome/browser/nacl_host/nacl_process_host.cc
@@ -25,7 +25,10 @@
 #include "base/strings/utf_string_conversions.h"
 #include "base/win/windows_version.h"
 #include "build/build_config.h"
+#include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/nacl_host/nacl_host_message_filter.h"
+#include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_switches.h"
 #include "components/nacl/browser/nacl_browser.h"
 #include "components/nacl/common/nacl_cmd_line.h"
@@ -36,6 +39,8 @@
 #include "content/public/browser/browser_child_process_host.h"
 #include "content/public/browser/browser_ppapi_host.h"
 #include "content/public/browser/child_process_data.h"
+#include "content/public/browser/render_view_host.h"
+#include "content/public/browser/site_instance.h"
 #include "content/public/common/child_process_host.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/process_type.h"
@@ -769,6 +774,56 @@ bool NaClProcessHost::SendStart() {
   return StartNaClExecution();
 }
 
+class BrowserPpapiHostDelegate : public content::BrowserPpapiHost::Delegate {
+  virtual void OnIdleState(bool idle,
+                           const base::FilePath& profile_data_directory,
+                           const content::RenderViewHost* render_view_host,
+                           const GURL& document_url) OVERRIDE {
+    DCHECK(render_view_host);
+    if (!render_view_host)
+      return;
+
+    content::SiteInstance* site_instance = render_view_host->GetSiteInstance();
+    DCHECK(site_instance);
+    if (!site_instance)
+      return;
+
+    extensions::ExtensionSystem* extension_system =
+        extensions::ExtensionSystem::GetForBrowserContext(
+            site_instance->GetBrowserContext());
+    DCHECK(extension_system);
+    if (!extension_system)
+      return;
+
+    const ExtensionService* extension_service =
+        extension_system->extension_service();
+    DCHECK(extension_service);
+    if (!extension_service)
+      return;
+
+    const extensions::Extension* extension =
+      extension_service->GetExtensionById(document_url.host(), false);
+    DCHECK(extension);
+    if (!extension)
+      return;
+
+    ExtensionProcessManager* pm = extension_system->process_manager();
+    DCHECK(pm);
+    if (!pm)
+      return;
+
+    if (idle) {
+      fprintf(stderr, "%s:%s:%d DecrementLazyKeepaliveCount\n",
+              __FILE__, __FUNCTION__, __LINE__);
+      pm->DecrementLazyKeepaliveCount(extension);
+    } else {
+      fprintf(stderr, "%s:%s:%d IncrementLazyKeepaliveCount\n",
+              __FILE__, __FUNCTION__, __LINE__);
+      pm->IncrementLazyKeepaliveCount(extension);
+    }
+  }
+};
+
 // This method is called when NaClProcessHostMsg_PpapiChannelCreated is
 // received or PpapiHostMsg_ChannelCreated is forwarded by our plugin
 // listener.
@@ -788,14 +843,15 @@ void NaClProcessHost::OnPpapiChannelCreated(
                               base::MessageLoopProxy::current().get()));
     // Create the browser ppapi host and enable PPAPI message dispatching to the
     // browser process.
-    ppapi_host_.reset(content::BrowserPpapiHost::CreateExternalPluginProcess(
+    ppapi_host_ = content::BrowserPpapiHost::CreateExternalPluginProcess(
+        new BrowserPpapiHostDelegate(),
         ipc_proxy_channel_.get(),  // sender
         permissions_,
         process_->GetData().handle,
         ipc_proxy_channel_.get(),
         nacl_host_message_filter_->render_process_id(),
         render_view_id_,
-        profile_directory_));
+        profile_directory_);
 
     ppapi::PpapiNaClChannelArgs args;
     args.off_the_record = nacl_host_message_filter_->off_the_record();