Introduce HostID and de-couple Extensions from "script injection System" [browser side]

The major refactor includes:
- Introduce HostID (a pair of |id, type|) to replace extension_id in browser
  side.
- Abstract UserScriptLoader to be a base class, and introduces
  a derived class ExtensionUserScriptLoader which is
  responsible for loading user scripts for extensions.
- In DeclarativeUserScriptManager, a master is created per
  extension/webUI.
- DeclarativeUserScriptManager becomes an
  ExtensionRegistryObserver and is responsible for clearing scripts
  for master objects when receive OnExensionUnloaded event.

BUG=437566

Review URL: https://codereview.chromium.org/822453002

Cr-Commit-Position: refs/heads/master@{#313402}

11 files changed, 110 insertions, 30 deletions

diff --git a/extensions/browser/api/declarative/declarative_rule.h b/extensions/browser/api/declarative/declarative_rule.h
index b612f27..8dd3837 100644
--- a/extensions/browser/api/declarative/declarative_rule.h
+++ b/extensions/browser/api/declarative/declarative_rule.h
@@ -23,6 +23,7 @@
 #include "components/url_matcher/url_matcher.h"
 #include "extensions/common/api/events.h"
 #include "extensions/common/extension.h"
+#include "extensions/common/host_id.h"
 
 namespace base {
 class Time;
@@ -152,6 +153,7 @@ class DeclarativeActionSet {
   // the extension API.
   static scoped_ptr<DeclarativeActionSet> Create(
       content::BrowserContext* browser_context,
+      const HostID& host_id,
       const Extension* extension,
       const AnyVector& actions,
       std::string* error,
@@ -230,6 +232,7 @@ class DeclarativeRule {
   static scoped_ptr<DeclarativeRule> Create(
       url_matcher::URLMatcherConditionFactory* url_matcher_condition_factory,
       content::BrowserContext* browser_context,
+      const HostID& host_id,
       const Extension* extension,
       base::Time extension_installation_time,
       linked_ptr<JsonRule> rule,
@@ -366,6 +369,7 @@ template<typename ActionT>
 scoped_ptr<DeclarativeActionSet<ActionT> >
 DeclarativeActionSet<ActionT>::Create(
     content::BrowserContext* browser_context,
+    const HostID& host_id,
     const Extension* extension,
     const AnyVector& actions,
     std::string* error,
@@ -378,7 +382,8 @@ DeclarativeActionSet<ActionT>::Create(
        i != actions.end(); ++i) {
     CHECK(i->get());
     scoped_refptr<const ActionT> action =
-        ActionT::Create(browser_context, extension, **i, error, bad_message);
+        ActionT::Create(
+            browser_context, host_id, extension, **i, error, bad_message);
     if (!error->empty() || *bad_message)
       return scoped_ptr<DeclarativeActionSet>();
     result.push_back(action);
@@ -455,6 +460,7 @@ scoped_ptr<DeclarativeRule<ConditionT, ActionT> >
 DeclarativeRule<ConditionT, ActionT>::Create(
     url_matcher::URLMatcherConditionFactory* url_matcher_condition_factory,
     content::BrowserContext* browser_context,
+    const HostID& host_id,
     const Extension* extension,
     base::Time extension_installation_time,
     linked_ptr<JsonRule> rule,
@@ -470,8 +476,8 @@ DeclarativeRule<ConditionT, ActionT>::Create(
 
   bool bad_message = false;
   scoped_ptr<ActionSet> actions =
-      ActionSet::Create(
-          browser_context, extension, rule->actions, error, &bad_message);
+      ActionSet::Create(browser_context, host_id, extension,
+                        rule->actions, error, &bad_message);
   if (bad_message) {
     // TODO(battre) Export concept of bad_message to caller, the extension
     // should be killed in case it is true.
diff --git a/extensions/browser/api/declarative/declarative_rule_unittest.cc b/extensions/browser/api/declarative/declarative_rule_unittest.cc
index 552145d..3c4163b 100644
--- a/extensions/browser/api/declarative/declarative_rule_unittest.cc
+++ b/extensions/browser/api/declarative/declarative_rule_unittest.cc
@@ -219,6 +219,7 @@ class SummingAction : public base::RefCounted<SummingAction> {
 
   static scoped_refptr<const SummingAction> Create(
       content::BrowserContext* browser_context,
+      const HostID& host_id,
       const Extension* extension,
       const base::Value& action,
       std::string* error,
@@ -270,7 +271,7 @@ TEST(DeclarativeActionTest, ErrorActionSet) {
   std::string error;
   bool bad = false;
   scoped_ptr<SummingActionSet> result =
-      SummingActionSet::Create(NULL, NULL, actions, &error, &bad);
+      SummingActionSet::Create(NULL, HostID(), NULL, actions, &error, &bad);
   EXPECT_EQ("the error", error);
   EXPECT_FALSE(bad);
   EXPECT_FALSE(result);
@@ -278,7 +279,8 @@ TEST(DeclarativeActionTest, ErrorActionSet) {
   actions.clear();
   actions.push_back(ScopedToLinkedPtr(ParseJson("{\"value\": 1}")));
   actions.push_back(ScopedToLinkedPtr(ParseJson("{\"bad\": 3}")));
-  result = SummingActionSet::Create(NULL, NULL, actions, &error, &bad);
+  result = SummingActionSet::Create(
+      NULL, HostID(), NULL, actions, &error, &bad);
   EXPECT_EQ("", error);
   EXPECT_TRUE(bad);
   EXPECT_FALSE(result);
@@ -295,7 +297,7 @@ TEST(DeclarativeActionTest, ApplyActionSet) {
   std::string error;
   bool bad = false;
   scoped_ptr<SummingActionSet> result =
-      SummingActionSet::Create(NULL, NULL, actions, &error, &bad);
+      SummingActionSet::Create(NULL, HostID(), NULL, actions, &error, &bad);
   EXPECT_EQ("", error);
   EXPECT_FALSE(bad);
   ASSERT_TRUE(result);
@@ -336,13 +338,15 @@ TEST(DeclarativeRuleTest, Create) {
 
   URLMatcher matcher;
   std::string error;
-  scoped_ptr<Rule> rule(Rule::Create(matcher.condition_factory(),
-                                     NULL,
-                                     extension.get(),
-                                     install_time,
-                                     json_rule,
-                                     Rule::ConsistencyChecker(),
-                                     &error));
+  scoped_ptr<Rule> rule(
+      Rule::Create(matcher.condition_factory(),
+                   NULL,
+                   HostID(HostID::EXTENSIONS, extension.get()->id()),
+                   extension.get(),
+                   install_time,
+                   json_rule,
+                   Rule::ConsistencyChecker(),
+                   &error));
   EXPECT_EQ("", error);
   ASSERT_TRUE(rule.get());
 
@@ -405,13 +409,15 @@ TEST(DeclarativeRuleTest, CheckConsistency) {
                  "  \"priority\": 200 \n"
                  "}"),
       json_rule.get()));
-  scoped_ptr<Rule> rule(Rule::Create(matcher.condition_factory(),
-                                     NULL,
-                                     extension.get(),
-                                     base::Time(),
-                                     json_rule,
-                                     base::Bind(AtLeastOneCondition),
-                                     &error));
+  scoped_ptr<Rule> rule(
+      Rule::Create(matcher.condition_factory(),
+                   NULL,
+                   HostID(HostID::EXTENSIONS, extension.get()->id()),
+                   extension.get(),
+                   base::Time(),
+                   json_rule,
+                   base::Bind(AtLeastOneCondition),
+                   &error));
   EXPECT_TRUE(rule);
   EXPECT_EQ("", error);
 
@@ -430,6 +436,7 @@ TEST(DeclarativeRuleTest, CheckConsistency) {
       json_rule.get()));
   rule = Rule::Create(matcher.condition_factory(),
                       NULL,
+                      HostID(HostID::EXTENSIONS, extension.get()->id()),
                       extension.get(),
                       base::Time(),
                       json_rule,
diff --git a/extensions/browser/api/declarative_webrequest/webrequest_action.cc b/extensions/browser/api/declarative_webrequest/webrequest_action.cc
index 1a777ce..6d79227 100644
--- a/extensions/browser/api/declarative_webrequest/webrequest_action.cc
+++ b/extensions/browser/api/declarative_webrequest/webrequest_action.cc
@@ -514,6 +514,7 @@ bool WebRequestAction::HasPermission(const InfoMap* extension_info_map,
 // static
 scoped_refptr<const WebRequestAction> WebRequestAction::Create(
     content::BrowserContext* browser_context,
+    const HostID& host_id,
     const Extension* extension,
     const base::Value& json_action,
     std::string* error,
diff --git a/extensions/browser/api/declarative_webrequest/webrequest_action.h b/extensions/browser/api/declarative_webrequest/webrequest_action.h
index 03fc796..fa01fd3 100644
--- a/extensions/browser/api/declarative_webrequest/webrequest_action.h
+++ b/extensions/browser/api/declarative_webrequest/webrequest_action.h
@@ -135,6 +135,7 @@ class WebRequestAction : public base::RefCounted<WebRequestAction> {
   // in case the input is syntactically unexpected.
   static scoped_refptr<const WebRequestAction> Create(
       content::BrowserContext* browser_context,
+      const HostID& host_id,
       const Extension* extension,
       const base::Value& json_action,
       std::string* error,
diff --git a/extensions/browser/api/declarative_webrequest/webrequest_rules_registry.cc b/extensions/browser/api/declarative_webrequest/webrequest_rules_registry.cc
index ae6f531..dcb0e6e 100644
--- a/extensions/browser/api/declarative_webrequest/webrequest_rules_registry.cc
+++ b/extensions/browser/api/declarative_webrequest/webrequest_rules_registry.cc
@@ -180,7 +180,8 @@ std::string WebRequestRulesRegistry::AddRulesImpl(
     DCHECK(registered_rules.find(rule_id) == registered_rules.end());
 
     scoped_ptr<WebRequestRule> webrequest_rule(WebRequestRule::Create(
-        url_matcher_.condition_factory(), browser_context(), extension,
+        url_matcher_.condition_factory(), browser_context(),
+        HostID(HostID::EXTENSIONS, extension->id()), extension,
         extension_installation_time, *rule,
         base::Bind(&Checker, base::Unretained(extension)), &error));
     if (!error.empty()) {
diff --git a/extensions/common/BUILD.gn b/extensions/common/BUILD.gn
index c23df44..ebfd09d 100644
--- a/extensions/common/BUILD.gn
+++ b/extensions/common/BUILD.gn
@@ -109,6 +109,7 @@ if (enable_extensions) {
       "file_util.h",
       "guest_view/guest_view_constants.cc",
       "guest_view/guest_view_constants.h",
+      "host_id.h",
       "image_util.cc",
       "image_util.h",
       "install_warning.cc",
diff --git a/extensions/common/host_id.h b/extensions/common/host_id.h
new file mode 100644
index 0000000..0044807
--- /dev/null
+++ b/extensions/common/host_id.h
@@ -0,0 +1,39 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef EXTENSIONS_COMMON_HOST_ID_H_
+#define EXTENSIONS_COMMON_HOST_ID_H_
+
+#include <string>
+
+// IDs of hosts who own user scripts.
+// A HostID is immutable after creation.
+struct HostID {
+  enum HostType { EXTENSIONS, WEBUI };
+
+  HostID() {}
+  HostID(HostType type, const std::string& id)
+      : type_(type), id_(id) {}
+
+  bool operator<(const HostID& host_id) const {
+    if (type_ != host_id.type())
+      return type_ < host_id.type();
+    else if (id_ != host_id.id())
+      return id_ < host_id.id();
+    return false;
+  }
+
+  HostType type() const { return type_; }
+  const std::string& id() const { return id_; }
+
+ private:
+  // The type of the host.
+  HostType type_;
+
+  // Similar to extension_id, host_id is a unique indentifier for a host,
+  // e.g., an Extension or WebUI.
+  std::string id_;
+};
+
+#endif  // EXTENSIONS_COMMON_HOST_ID_H_
diff --git a/extensions/common/user_script.cc b/extensions/common/user_script.cc
index 4410290..b8ba22e 100644
--- a/extensions/common/user_script.cc
+++ b/extensions/common/user_script.cc
@@ -138,13 +138,13 @@ void UserScript::File::Unpickle(const ::Pickle& pickle, PickleIterator* iter) {
 void UserScript::Pickle(::Pickle* pickle) const {
   // Write the simple types to the pickle.
   pickle->WriteInt(run_location());
-  pickle->WriteString(extension_id());
   pickle->WriteInt(user_script_id_);
   pickle->WriteBool(emulate_greasemonkey());
   pickle->WriteBool(match_all_frames());
   pickle->WriteBool(match_about_blank());
   pickle->WriteBool(is_incognito_enabled());
 
+  PickleHostID(pickle, host_id_);
   PickleGlobs(pickle, globs_);
   PickleGlobs(pickle, exclude_globs_);
   PickleURLPatternSet(pickle, url_set_);
@@ -162,6 +162,11 @@ void UserScript::PickleGlobs(::Pickle* pickle,
   }
 }
 
+void UserScript::PickleHostID(::Pickle* pickle, const HostID& host_id) const {
+  pickle->WriteInt(host_id.type());
+  pickle->WriteString(host_id.id());
+}
+
 void UserScript::PickleURLPatternSet(::Pickle* pickle,
                                      const URLPatternSet& pattern_list) const {
   pickle->WriteSizeT(pattern_list.patterns().size());
@@ -188,13 +193,13 @@ void UserScript::Unpickle(const ::Pickle& pickle, PickleIterator* iter) {
   CHECK(run_location >= 0 && run_location < RUN_LOCATION_LAST);
   run_location_ = static_cast<RunLocation>(run_location);
 
-  CHECK(iter->ReadString(&extension_id_));
   CHECK(iter->ReadInt(&user_script_id_));
   CHECK(iter->ReadBool(&emulate_greasemonkey_));
   CHECK(iter->ReadBool(&match_all_frames_));
   CHECK(iter->ReadBool(&match_about_blank_));
   CHECK(iter->ReadBool(&incognito_enabled_));
 
+  UnpickleHostID(pickle, iter, &host_id_);
   UnpickleGlobs(pickle, iter, &globs_);
   UnpickleGlobs(pickle, iter, &exclude_globs_);
   UnpickleURLPatternSet(pickle, iter, &url_set_);
@@ -215,6 +220,16 @@ void UserScript::UnpickleGlobs(const ::Pickle& pickle, PickleIterator* iter,
   }
 }
 
+void UserScript::UnpickleHostID(const ::Pickle& pickle,
+                                PickleIterator* iter,
+                                HostID* host_id) {
+  int type = 0;
+  std::string id;
+  CHECK(iter->ReadInt(&type));
+  CHECK(iter->ReadString(&id));
+  *host_id = HostID(static_cast<HostID::HostType>(type), id);
+}
+
 void UserScript::UnpickleURLPatternSet(const ::Pickle& pickle,
                                        PickleIterator* iter,
                                        URLPatternSet* pattern_list) {
diff --git a/extensions/common/user_script.h b/extensions/common/user_script.h
index 5a27315..6069161 100644
--- a/extensions/common/user_script.h
+++ b/extensions/common/user_script.h
@@ -11,6 +11,7 @@
 #include "base/basictypes.h"
 #include "base/files/file_path.h"
 #include "base/strings/string_piece.h"
+#include "extensions/common/host_id.h"
 #include "extensions/common/url_pattern.h"
 #include "extensions/common/url_pattern_set.h"
 #include "url/gurl.h"
@@ -194,8 +195,10 @@ class UserScript {
   FileList& css_scripts() { return css_scripts_; }
   const FileList& css_scripts() const { return css_scripts_; }
 
-  const std::string& extension_id() const { return extension_id_; }
-  void set_extension_id(const std::string& id) { extension_id_ = id; }
+  const std::string& extension_id() const { return host_id_.id(); }
+
+  const HostID& host_id() const { return host_id_; }
+  void set_host_id(const HostID& host_id) { host_id_ = host_id; }
 
   int id() const { return user_script_id_; }
   void set_id(int id) { user_script_id_ = id; }
@@ -203,7 +206,7 @@ class UserScript {
   bool is_incognito_enabled() const { return incognito_enabled_; }
   void set_incognito_enabled(bool enabled) { incognito_enabled_ = enabled; }
 
-  bool is_standalone() const { return extension_id_.empty(); }
+  bool is_standalone() const { return extension_id().empty(); }
 
   // Returns true if the script should be applied to the specified URL, false
   // otherwise.
@@ -222,6 +225,7 @@ class UserScript {
   // Pickle helper functions used to pickle the individual types of components.
   void PickleGlobs(::Pickle* pickle,
                    const std::vector<std::string>& globs) const;
+  void PickleHostID(::Pickle* pickle, const HostID& host_id) const;
   void PickleURLPatternSet(::Pickle* pickle,
                            const URLPatternSet& pattern_list) const;
   void PickleScripts(::Pickle* pickle, const FileList& scripts) const;
@@ -229,6 +233,9 @@ class UserScript {
   // Unpickle helper functions used to unpickle individual types of components.
   void UnpickleGlobs(const ::Pickle& pickle, PickleIterator* iter,
                      std::vector<std::string>* globs);
+  void UnpickleHostID(const ::Pickle& pickle,
+                      PickleIterator* iter,
+                      HostID* host_id);
   void UnpickleURLPatternSet(const ::Pickle& pickle, PickleIterator* iter,
                              URLPatternSet* pattern_list);
   void UnpickleScripts(const ::Pickle& pickle, PickleIterator* iter,
@@ -267,9 +274,9 @@ class UserScript {
   // List of css scripts defined in content_scripts
   FileList css_scripts_;
 
-  // The ID of the extension this script is a part of, if any. Can be empty if
-  // the script is a "standlone" user script.
-  std::string extension_id_;
+  // The ID of the host this script is a part of. The |ID| of the
+  // |host_id| can be empty if the script is a "standlone" user script.
+  HostID host_id_;
 
   // The globally-unique id associated with this user script. Defaults to
   // -1 for invalid.
diff --git a/extensions/common/user_script_unittest.cc b/extensions/common/user_script_unittest.cc
index 589b555..4a964f7 100644
--- a/extensions/common/user_script_unittest.cc
+++ b/extensions/common/user_script_unittest.cc
@@ -193,7 +193,8 @@ TEST(ExtensionUserScriptTest, Pickle) {
   const int64 kId = 12;
   script1.set_id(kId);
   const std::string kExtensionId = "foo";
-  script1.set_extension_id(kExtensionId);
+  HostID id(HostID::EXTENSIONS, kExtensionId);
+  script1.set_host_id(id);
 
   Pickle pickle;
   script1.Pickle(&pickle);
diff --git a/extensions/extensions.gyp b/extensions/extensions.gyp
index 1197c5c..0977c5d 100644
--- a/extensions/extensions.gyp
+++ b/extensions/extensions.gyp
@@ -88,6 +88,7 @@
         'common/cast/cast_cert_validator.h',
         'common/common_manifest_handlers.cc',
         'common/common_manifest_handlers.h',
+        'common/host_id.h',
         'common/csp_validator.cc',
         'common/csp_validator.h',
         'common/dom_action_types.h',