Add logging in DefaultComponentInstaller to help investigate a bug

components/component_updater/default_component_installer.cc

 // Copyright 2014 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.
 
 #include "components/component_updater/default_component_installer.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 134 matching lines @@
 }
 
 bool DefaultComponentInstaller::Uninstall() {
   DCHECK(thread_checker_.CalledOnValidThread());
   task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&DefaultComponentInstaller::UninstallOnTaskRunner, this));
   return true;
 }
 
+// TODO(xhwang): The following LOG(WARNING) messages are added to help
+// investigate http://crbug.com/614745. Remove redundant checks or convent them
+// to VLOG(1) after investigation is completed.
 bool DefaultComponentInstaller::FindPreinstallation() {
   base::FilePath path;
-  if (!PathService::Get(DIR_COMPONENT_PREINSTALLED, &path))
+  if (!PathService::Get(DIR_COMPONENT_PREINSTALLED, &path)) {
+    LOG(WARNING) << "DIR_COMPONENT_PREINSTALLED does not exist.";
     return false;
+  }
+
   path = path.Append(installer_traits_->GetRelativeInstallDir());
-  if (!base::PathExists(path))
+  if (!base::PathExists(path)) {
+    LOG(WARNING) << "Relative install dir does not exist: "
+                 << path.MaybeAsASCII();
     return false;
+  }
+
   std::unique_ptr<base::DictionaryValue> manifest =
       update_client::ReadManifest(path);
-  if (!manifest || !installer_traits_->VerifyInstallation(*manifest, path))
+  if (!manifest) {
+    LOG(WARNING) << "Manifest does not exist: " << path.MaybeAsASCII();
     return false;
+  }
+
+  if (!installer_traits_->VerifyInstallation(*manifest, path)) {
+    LOG(WARNING) << "Installation verification failed: " << path.MaybeAsASCII();
+    return false;
+  }
+
   std::string version_lexical;
-  if (!manifest->GetStringASCII("version", &version_lexical))
+  if (!manifest->GetStringASCII("version", &version_lexical)) {
+    LOG(WARNING) << "Failed to get component version from the manifest.";
     return false;
+  }
+
   const base::Version version(version_lexical);
-  if (!version.IsValid())
+  if (!version.IsValid()) {
+    LOG(WARNING) << "Version in the manifest is invalid:" << version_lexical;
     return false;
+  }
+
+  LOG(WARNING) << "Preinstalled component found for "
+               << installer_traits_->GetName() << " at " << path.MaybeAsASCII()
+               << " with version " << version << ".";
+
   current_install_dir_ = path;
   current_manifest_ = std::move(manifest);
   current_version_ = version;
   return true;
 }
 
 void DefaultComponentInstaller::StartRegistration(ComponentUpdateService* cus) {
+  LOG(WARNING) << __FUNCTION__ << " for " << installer_traits_->GetName();
   DCHECK(task_runner_.get());
   DCHECK(task_runner_->RunsTasksOnCurrentThread());
 
   base::Version latest_version(kNullVersion);
 
   // First check for an installation set up alongside Chrome itself.
   if (FindPreinstallation())
     latest_version = current_version_;
 
   // Then check for a higher-versioned user-wide installation.
@@ skipping 95 matching lines @@
   // Delete the base directory if it's empty now.
   if (base::IsDirectoryEmpty(base_dir)) {
     if (base::DeleteFile(base_dir, false))
       DLOG(ERROR) << "Couldn't delete " << base_dir.value();
   }
 }
 
 void DefaultComponentInstaller::FinishRegistration(
     ComponentUpdateService* cus,
     const base::Closure& callback) {
+  LOG(WARNING) << __FUNCTION__ << " for " << installer_traits_->GetName();
   DCHECK(thread_checker_.CalledOnValidThread());
+
   if (installer_traits_->CanAutoUpdate()) {
     CrxComponent crx;
     crx.name = installer_traits_->GetName();
     crx.requires_network_encryption =
         installer_traits_->RequiresNetworkEncryption();
     crx.installer = this;
     crx.version = current_version_;
     crx.fingerprint = current_fingerprint_;
     installer_traits_->GetHash(&crx.pk_hash);
     if (!cus->RegisterComponent(crx)) {
-      NOTREACHED() << "Component registration failed for "
+      LOG(WARNING) << "Component registration failed for "
                    << installer_traits_->GetName();
       return;
     }
 
     if (!callback.is_null())
       callback.Run();
   }
 
-  if (!current_manifest_)
+  if (!current_manifest_) {
+    LOG(WARNING) << "No component found for " << installer_traits_->GetName();
     return;
+  }
 
   std::unique_ptr<base::DictionaryValue> manifest_copy(
       current_manifest_->DeepCopy());
   ComponentReady(std::move(manifest_copy));
 }
 
 void DefaultComponentInstaller::ComponentReady(
     std::unique_ptr<base::DictionaryValue> manifest) {
   VLOG(1) << "Component ready, version " << current_version_.GetString()
           << " in " << current_install_dir_.value();
   installer_traits_->ComponentReady(current_version_, current_install_dir_,
                                     std::move(manifest));
 }
 
 }  // namespace component_updater