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

chrome/browser/extensions/api/declarative_content/content_action.cc

Index: chrome/browser/extensions/api/declarative_content/content_action.cc
diff --git a/chrome/browser/extensions/api/declarative_content/content_action.cc b/chrome/browser/extensions/api/declarative_content/content_action.cc
index e0ff006e16d05bc8418a6014f331bb6300debe48..bc764f4841c8a2066bf2d793958ec5aa4128bcb8 100644
--- a/chrome/browser/extensions/api/declarative_content/content_action.cc
+++ b/chrome/browser/extensions/api/declarative_content/content_action.cc
@@ -7,6 +7,7 @@
 #include <map>
 
 #include "base/lazy_instance.h"
+#include "base/memory/linked_ptr.h"
 #include "base/strings/stringprintf.h"
 #include "base/values.h"
 #include "chrome/browser/extensions/api/declarative_content/content_constants.h"
@@ -22,6 +23,7 @@
 #include "content/public/browser/web_contents.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/browser/extension_system.h"
+#include "extensions/common/consumer.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/extension_messages.h"
 #include "ui/gfx/image/image.h"
@@ -239,6 +241,32 @@ struct ContentActionFactory {
 base::LazyInstance<ContentActionFactory>::Leaky
     g_content_action_factory = LAZY_INSTANCE_INITIALIZER;
 
+using RequestContentScriptKey = RequestContentScript::RequestKey;
+
+using RequestContentScriptKeyToIDMap =
+    std::map<RequestContentScriptKey, linked_ptr<ConsumerID>>;
+
+// A map of ConsumerIDs for the given RequestContentScript ids.
+// Different types of input ids will define their own maps to store the
+// mappings from ids to ConsumerIDs.
+static base::LazyInstance<RequestContentScriptKeyToIDMap>
+      request_content_script_key_to_id_map_ = LAZY_INSTANCE_INITIALIZER;
+
+const ConsumerID& GetConsumerID(
+    const RequestContentScriptKey& key,
+    ConsumerID::HostType host_type,
+    ConsumerID::InstanceType instance_type) {
+  RequestContentScriptKeyToIDMap::iterator it =
+      request_content_script_key_to_id_map_.Get().find(key);
+  if (it != request_content_script_key_to_id_map_.Get().end())
+    return *(it->second.get());
+
+  linked_ptr<ConsumerID> consumer_id(new ConsumerID(
+      host_type, key.host_id, instance_type, ConsumerID::GetNextID()));
+  request_content_script_key_to_id_map_.Get()[key] = consumer_id;
+  return *(consumer_id.get());
+}
+
 }  // namespace
 
 //
@@ -350,11 +378,13 @@ RequestContentScript::RequestContentScript(
     content::BrowserContext* browser_context,
     const Extension* extension,
     const ScriptData& script_data) {
-  InitScript(extension, script_data);
-
+  const RequestKey key(extension->id());
+  const ConsumerID& consumer_id = GetConsumerID(
+      key, ConsumerID::EXTENSIONS, ConsumerID::TAB);
   master_ = ExtensionSystem::Get(browser_context)
                 ->declarative_user_script_manager()
-                ->GetDeclarativeUserScriptMasterByID(extension->id());
+                ->GetDeclarativeUserScriptMasterByID(consumer_id);
+  InitScript(extension, script_data);
   AddScript();
 }
 
@@ -362,21 +392,20 @@ RequestContentScript::RequestContentScript(
     DeclarativeUserScriptMaster* master,
     const Extension* extension,
     const ScriptData& script_data) {
+  master_.reset(master);
   InitScript(extension, script_data);
-
-  master_ = master;
   AddScript();
 }
 
 RequestContentScript::~RequestContentScript() {
-  DCHECK(master_);
+  DCHECK(master_.get());
   master_->RemoveScript(script_);
 }
 
 void RequestContentScript::InitScript(const Extension* extension,
                                       const ScriptData& script_data) {
   script_.set_id(UserScript::GenerateUserScriptID());
-  script_.set_extension_id(extension->id());
+  script_.set_consumer_id(master_->consumer_id());
   script_.set_run_location(UserScript::BROWSER_DRIVEN);
   script_.set_match_all_frames(script_data.all_frames);
   script_.set_match_about_blank(script_data.match_about_blank);