Fix event page process cleanup when running in --isolate-extensions mode.

extensions/browser/process_manager.cc

Index: extensions/browser/process_manager.cc
diff --git a/extensions/browser/process_manager.cc b/extensions/browser/process_manager.cc
index a71b4c9d89fdb29a9494bf4d2694316f60299a7f..7bb297a718f5f1d68d8882e89d896b9fccb0def9 100644
--- a/extensions/browser/process_manager.cc
+++ b/extensions/browser/process_manager.cc
@@ -297,7 +297,6 @@ void ProcessManager::UnregisterRenderFrameHost(
     content::RenderFrameHost* render_frame_host) {
   ExtensionRenderFrames::iterator frame =
       all_extension_frames_.find(render_frame_host);
-
   if (frame != all_extension_frames_.end()) {
     std::string extension_id = GetExtensionID(render_frame_host);
     // Keepalive count, balanced in RegisterRenderFrame.
@@ -569,24 +568,34 @@ void ProcessManager::OnNetworkRequestStarted(
     uint64_t request_id) {
   ExtensionHost* host = GetBackgroundHostForExtension(
       GetExtensionID(render_frame_host));
-  auto result = pending_network_requests_.insert(request_id);
+  if (!host || !IsFrameInExtensionHost(host, render_frame_host))
+    return;
+
+  auto result =
+      pending_network_requests_.insert(std::make_pair(request_id, host));
   DCHECK(result.second) << "Duplicate network request IDs.";
-  if (host && IsFrameInExtensionHost(host, render_frame_host)) {
-    IncrementLazyKeepaliveCount(host->extension());
-    host->OnNetworkRequestStarted(request_id);
-  }
+
+  IncrementLazyKeepaliveCount(host->extension());
+  host->OnNetworkRequestStarted(request_id);
 }
 
 void ProcessManager::OnNetworkRequestDone(
     content::RenderFrameHost* render_frame_host,
     uint64_t request_id) {
-  ExtensionHost* host = GetBackgroundHostForExtension(
-      GetExtensionID(render_frame_host));
-  if (host && IsFrameInExtensionHost(host, render_frame_host)) {
-    host->OnNetworkRequestDone(request_id);
-    if (pending_network_requests_.erase(request_id))
-      DecrementLazyKeepaliveCount(host->extension());
-  }
+  auto result = pending_network_requests_.find(request_id);
+  if (result == pending_network_requests_.end())
+    return;
+
+  ExtensionHost* host = result->second;

[Devlin, 2016/06/01 21:39:02]

It might be worth noting that |host| can be invalid here (I know that's why
you're checking on line 592, but future us might not remember that it's unsafe
to access this on line 590 ;))

[nasko, 2016/06/01 23:17:51]

Done.

+  pending_network_requests_.erase(result);
+
+  if (background_hosts_.find(host) == background_hosts_.end())
+    return;
+
+  DCHECK(IsFrameInExtensionHost(host, render_frame_host));
+
+  host->OnNetworkRequestDone(request_id);
+  DecrementLazyKeepaliveCount(host->extension());
 }
 
 void ProcessManager::CancelSuspend(const Extension* extension) {