Add a function triggering extension installed to ExtensionRegistryObserver.

This can be replace chrome::NOTIFICATION_EXTENSION_INSTALLED with ExtensionRegistryObserver.

And apply it to WebStoreInstaller and InstallTracker.

R=kalman@chromium.org
BUG=354459
TEST=unit_test, manual(install app from webstore)

Review URL: https://codereview.chromium.org/279073003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@272143 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 53 insertions, 0 deletions

diff --git a/extensions/browser/extension_registry.cc b/extensions/browser/extension_registry.cc
index ac6c274..76783f0 100644
--- a/extensions/browser/extension_registry.cc
+++ b/extensions/browser/extension_registry.cc
@@ -53,6 +53,18 @@ void ExtensionRegistry::TriggerOnUnloaded(
                     OnExtensionUnloaded(browser_context_, extension, reason));
 }
 
+void ExtensionRegistry::TriggerOnWillBeInstalled(const Extension* extension,
+                                                 bool is_update,
+                                                 const std::string& old_name) {
+  DCHECK(is_update ==
+         GenerateInstalledExtensionsSet()->Contains(extension->id()));
+  DCHECK(is_update == !old_name.empty());
+  FOR_EACH_OBSERVER(ExtensionRegistryObserver,
+                    observers_,
+                    OnExtensionWillBeInstalled(
+                        browser_context_, extension, is_update, old_name));
+}
+
 const Extension* ExtensionRegistry::GetExtensionById(const std::string& id,
                                                      int include_mask) const {
   std::string lowercase_id = StringToLowerASCII(id);
diff --git a/extensions/browser/extension_registry.h b/extensions/browser/extension_registry.h
index d8df24b..65ee751 100644
--- a/extensions/browser/extension_registry.h
+++ b/extensions/browser/extension_registry.h
@@ -74,6 +74,14 @@ class ExtensionRegistry : public KeyedService {
   void TriggerOnUnloaded(const Extension* extension,
                          UnloadedExtensionInfo::Reason reason);
 
+  // If this is a fresh install then |is_update| is false and there must not be
+  // any installed extension with |extension|'s ID. If this is an update then
+  // |is_update| is true and must be an installed extension with |extension|'s
+  // ID, and |old_name| must be non-empty.
+  void TriggerOnWillBeInstalled(const Extension* extension,
+                                bool is_update,
+                                const std::string& old_name);
+
   // Find an extension by ID using |include_mask| to pick the sets to search:
   //  * enabled_extensions()     --> ExtensionRegistry::ENABLED
   //  * disabled_extensions()    --> ExtensionRegistry::DISABLED
diff --git a/extensions/browser/extension_registry_observer.h b/extensions/browser/extension_registry_observer.h
index 5880add..6ad0666 100644
--- a/extensions/browser/extension_registry_observer.h
+++ b/extensions/browser/extension_registry_observer.h
@@ -33,6 +33,21 @@ class ExtensionRegistryObserver {
   virtual void OnExtensionUnloaded(content::BrowserContext* browser_context,
                                    const Extension* extension,
                                    UnloadedExtensionInfo::Reason reason) {}
+
+  // Called when |extension| is about to be installed. |is_update| is true if
+  // the installation is the result of it updating, in which case |old_name| is
+  // the name of the extension's previous version.
+  // The ExtensionRegistry will not be tracking |extension| at the time this
+  // event is fired, but will be immediately afterwards (note: not necessarily
+  // enabled; it might be installed in the disabled or even blacklisted sets,
+  // for example).
+  // Note that it's much more common to care about extensions being loaded
+  // (OnExtensionLoaded).
+  virtual void OnExtensionWillBeInstalled(
+      content::BrowserContext* browser_context,
+      const Extension* extension,
+      bool is_update,
+      const std::string& old_name) {}
 };
 
 }  // namespace extensions
diff --git a/extensions/browser/extension_registry_unittest.cc b/extensions/browser/extension_registry_unittest.cc
index f212f6c..8281ee0 100644
--- a/extensions/browser/extension_registry_unittest.cc
+++ b/extensions/browser/extension_registry_unittest.cc
@@ -7,6 +7,7 @@
 #include <string>
 
 #include "base/memory/ref_counted.h"
+#include "base/strings/string_util.h"
 #include "extensions/browser/extension_registry_observer.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/test_util.h"
@@ -37,10 +38,12 @@ class TestObserver : public ExtensionRegistryObserver {
   void Reset() {
     loaded_.clear();
     unloaded_.clear();
+    installed_.clear();
   }
 
   const ExtensionList& loaded() { return loaded_; }
   const ExtensionList& unloaded() { return unloaded_; }
+  const ExtensionList& installed() { return installed_; }
 
  private:
   virtual void OnExtensionLoaded(content::BrowserContext* browser_context,
@@ -55,8 +58,17 @@ class TestObserver : public ExtensionRegistryObserver {
     unloaded_.push_back(extension);
   }
 
+  virtual void OnExtensionWillBeInstalled(
+      content::BrowserContext* browser_context,
+      const Extension* extension,
+      bool is_update,
+      const std::string& old_name) OVERRIDE {
+    installed_.push_back(extension);
+  }
+
   ExtensionList loaded_;
   ExtensionList unloaded_;
+  ExtensionList installed_;
 };
 
 TEST_F(ExtensionRegistryTest, FillAndClearRegistry) {
@@ -215,13 +227,19 @@ TEST_F(ExtensionRegistryTest, Observer) {
 
   EXPECT_TRUE(observer.loaded().empty());
   EXPECT_TRUE(observer.unloaded().empty());
+  EXPECT_TRUE(observer.installed().empty());
 
   scoped_refptr<const Extension> extension =
       test_util::CreateExtensionWithID("id");
 
+  registry.TriggerOnWillBeInstalled(extension, false, base::EmptyString());
+  EXPECT_TRUE(HasSingleExtension(observer.installed(), extension.get()));
+
   registry.AddEnabled(extension);
   registry.TriggerOnLoaded(extension);
 
+  registry.TriggerOnWillBeInstalled(extension, true, "foo");
+
   EXPECT_TRUE(HasSingleExtension(observer.loaded(), extension.get()));
   EXPECT_TRUE(observer.unloaded().empty());
   observer.Reset();