Don't send unnecessary ExtensionMsg_Loaded IPCs.

Each time ExtensionMsg_Loaded is sent it re-creates the set of Extensions it
gives, invalidating the existing ones. This means that anything that holds onto
Extensions for long periods of time - like ScriptContextSet - can end up in
situations where they have an Extension with the same ID as an installed
Extension, but different in pointer equality.

It turns out that we send ExtensionMsg_Loaded every time a RenderViewHost is
created, but it should only be send every time a RenderProcessHost is created,
because the Extension sets are process-wide.

While this bug is fundamental, one way it manifests itself is by the
chrome.permissions.request API not updating the JavaScript context when
permissions are granted.

BUG=435141

Review URL: https://codereview.chromium.org/1142993002

Cr-Commit-Position: refs/heads/master@{#332720}

1 files changed, 8 insertions, 1 deletions

diff --git a/extensions/renderer/dispatcher.h b/extensions/renderer/dispatcher.h
index f85c1ad..982473b 100644
--- a/extensions/renderer/dispatcher.h
+++ b/extensions/renderer/dispatcher.h
@@ -137,10 +137,18 @@ class Dispatcher : public content::RenderProcessObserver,
   bool WasWebRequestUsedBySomeExtensions() const { return webrequest_used_; }
 
  private:
+  // The RendererPermissionsPolicyDelegateTest.CannotScriptWebstore test needs
+  // to call LoadExtensionForTest and the OnActivateExtension IPCs.
   friend class ::ChromeRenderViewTest;
   FRIEND_TEST_ALL_PREFIXES(RendererPermissionsPolicyDelegateTest,
                            CannotScriptWebstore);
 
+  // Inserts an Extension into |extensions_|. Normally the only way to do this
+  // would be through the ExtensionMsg_Loaded IPC (OnLoaded) but this can't be
+  // triggered for tests, because in the process of serializing then
+  // deserializing the IPC, Extension IDs manually set for testing are lost.
+  void LoadExtensionForTest(const Extension* extension);
+
   // RenderProcessObserver implementation:
   bool OnControlMessageReceived(const IPC::Message& message) override;
   void WebKitInitialized() override;
@@ -158,7 +166,6 @@ class Dispatcher : public content::RenderProcessObserver,
   void OnDispatchOnDisconnect(int port_id, const std::string& error_message);
   void OnLoaded(
       const std::vector<ExtensionMsg_Loaded_Params>& loaded_extensions);
-  void OnLoadedInternal(scoped_refptr<const Extension> extension);
   void OnMessageInvoke(const std::string& extension_id,
                        const std::string& module_name,
                        const std::string& function_name,