New Task Manager - Phase 1.3.2.B: Implement Tab Contents Task Providing (Prerender)

chrome/browser/prerender/prerender_contents.cc

 // Copyright (c) 2012 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 "chrome/browser/prerender/prerender_contents.h"
 
 #include <algorithm>
 #include <functional>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/history/history_tab_helper.h"
 #include "chrome/browser/prerender/prerender_field_trial.h"
 #include "chrome/browser/prerender/prerender_final_status.h"
 #include "chrome/browser/prerender/prerender_handle.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "chrome/browser/prerender/prerender_manager_factory.h"
 #include "chrome/browser/prerender/prerender_resource_throttle.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/task_management/web_contents_tags.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/tab_helpers.h"
 #include "chrome/browser/ui/web_contents_sizer.h"
 #include "chrome/common/prerender_messages.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/common/url_constants.h"
 #include "components/history/core/browser/history_types.h"
 #include "content/public/browser/browser_child_process_host.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_service.h"
@@ skipping 240 matching lines @@
   // control group.
   if (prerender_manager_->IsControlGroup())
     return;
 
   prerendering_has_started_ = true;
 
   prerender_contents_.reset(CreateWebContents(session_storage_namespace));
   TabHelpers::AttachTabHelpers(prerender_contents_.get());
   content::WebContentsObserver::Observe(prerender_contents_.get());
 
+#if defined(ENABLE_TASK_MANAGER)

[ncarter (slow), 2015/06/19 19:50:51]

This is okay, but I wonder, would it be more elegant if we put these #defines
inside of the bodies of the methods of WebContentsTags. Basically, all of
WebContentsTags would be a no-op if ENABLE_TASK_MANAGER were false?

[afakhry, 2015/06/19 21:49:22]

Unfortunately, it has to be done at the call site or otherwise there will be a
linking error ... task_manager_source_files are only included if
enable_task_manager==1 in the gyp files. enable_task_manager is 0 for ios and
android on the gn builds and I think is 0 only for android on the gyp builds.
See the build bots that failed the build in the previous patch.

See also:
https://code.google.com/p/chromium/codesearch#search/&q=%22enable_task_manage...

[ncarter (slow), 2015/06/20 04:34:47]

What I was advocating, was to add the web_content_tags.cc (and just that file)
back so that it's compiled on the ios/android build. But I am okay with the
#defines as they are.

[gavinp, 2015/06/22 18:40:15]

I like Nick's suggestion. That way, simpler callers like prerender_contents.cc
won't need to change when we remove the parameter and launch! It removes the
conditionals from many call sites that aren't particularly dependent on the new
messaging for the task manager.

+  // Tag the prerender contents with the task-manager specific prerender tag, so

[ncarter (slow), 2015/06/19 19:50:51]

"task-manager" -> "task manager". Also below.

[afakhry, 2015/06/19 21:49:22]

Done.

+  // that it shows up in the task manager.
+  task_management::WebContentsTags::CreateForPrerenderContents(
+      prerender_contents_.get());
+#endif  // defined(ENABLE_TASK_MANAGER)
+
   web_contents_delegate_.reset(new WebContentsDelegateImpl(this));
   prerender_contents_.get()->SetDelegate(web_contents_delegate_.get());
   // Set the size of the prerender WebContents.
   ResizeWebContents(prerender_contents_.get(), size_);
 
   // TODO(davidben): This logic assumes each prerender has at most one
   // route. https://crbug.com/440544
   child_id_ = GetRenderViewHost()->GetProcess()->GetID();
   route_id_ = GetRenderViewHost()->GetRoutingID();
 
@@ skipping 372 matching lines @@
   size_t private_bytes, shared_bytes;
   if (metrics->GetMemoryBytes(&private_bytes, &shared_bytes) &&
       private_bytes > prerender_manager_->config().max_bytes) {
     Destroy(FINAL_STATUS_MEMORY_LIMIT_EXCEEDED);
   }
 }
 
 WebContents* PrerenderContents::ReleasePrerenderContents() {
   prerender_contents_->SetDelegate(NULL);
   content::WebContentsObserver::Observe(NULL);
+
+#if defined(ENABLE_TASK_MANAGER)
+  // Here we have to clear the task-manager tag we added earlier to our
+  // WebContents since it's no longer a prerender content.
+  task_management::WebContentsTags::ClearTag(prerender_contents_.get());
+#endif  // defined(ENABLE_TASK_MANAGER)
+
   return prerender_contents_.release();
 }
 
 RenderViewHost* PrerenderContents::GetRenderViewHostMutable() {
   return const_cast<RenderViewHost*>(GetRenderViewHost());
 }
 
 const RenderViewHost* PrerenderContents::GetRenderViewHost() const {
   if (!prerender_contents_.get())
     return NULL;
@@ skipping 55 matching lines @@
 void PrerenderContents::AddResourceThrottle(
     const base::WeakPtr<PrerenderResourceThrottle>& throttle) {
   resource_throttles_.push_back(throttle);
 }
 
 void PrerenderContents::AddNetworkBytes(int64 bytes) {
   network_bytes_ += bytes;
 }
 
 }  // namespace prerender