Revert of Revert of Introduce HostID and de-couple Extensions from "script injection System" [browser side] (patchset #2 id:270001 of https://codereview.chromium.org/899983002/)

Reason for revert:
It turns out that the crash wasn't caused by this CL.

Original issue's description:
> Revert of Introduce HostID and de-couple Extensions from "script injection System" [browser side] (patchset #20 id:760001 of https://codereview.chromium.org/822453002/)
>
> Reason for revert:
> It might cause the crash https://code.google.com/p/chromium/issues/detail?id=454917.
>
> Original issue's description:
> > 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
> >
> > Committed: https://crrev.com/b88fe3dc1072501bdd105fd95a8b3bc453fd2aa7
> > Cr-Commit-Position: refs/heads/master@{#313402}
>
> TBR=fsamuel@chromium.org,rdevlin.cronin@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=437566
>
> Committed: https://crrev.com/5eb894ea21637241e9a78fb9c2737d40d6dbf575
> Cr-Commit-Position: refs/heads/master@{#314631}

TBR=fsamuel@chromium.org,rdevlin.cronin@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=437566

Review URL: https://codereview.chromium.org/903743002

Cr-Commit-Position: refs/heads/master@{#314807}

1 files changed, 17 insertions, 2 deletions

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) {