Plugin Power Saver: Restrict Power Saver to cross-origin.

content/renderer/pepper/pepper_plugin_instance_impl.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 "content/renderer/pepper/pepper_plugin_instance_impl.h"
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
@@ skipping 565 matching lines @@
     }
   }
 
   RendererPpapiHostImpl* host_impl = module_->renderer_ppapi_host();
   resource_creation_ = host_impl->CreateInProcessResourceCreationAPI(this);
 
   if (GetContentClient()->renderer() &&  // NULL in unit tests.
       GetContentClient()->renderer()->IsExternalPepperPlugin(module->name()))
     external_document_load_ = true;
 
-  // TODO(tommycli): Insert heuristics to determine whether plugin content
-  // is peripheral here.
-  bool is_peripheral_content = true;
-  power_saver_enabled_ = is_peripheral_content &&
-      module->name() == kFlashPluginName &&
-      CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kEnablePluginPowerSaver);
+  power_saver_enabled_ = CommandLine::ForCurrentProcess()->HasSwitch(
+                             switches::kEnablePluginPowerSaver) &&
+                         IsPeripheralContent();
 
   if (power_saver_enabled_) {
     throttler_.reset(new PepperPluginInstanceThrottler(
         base::Bind(&PepperPluginInstanceImpl::SetPluginThrottled,
                    weak_factory_.GetWeakPtr(), true /* throttled */)));
   }
 }
 
 PepperPluginInstanceImpl::~PepperPluginInstanceImpl() {
   DCHECK(!fullscreen_container_);
@@ skipping 2689 matching lines @@
   } else {
     // Running out-of-process. Initiate an IPC call to notify the plugin
     // process.
     ppapi::proxy::HostDispatcher* dispatcher =
         ppapi::proxy::HostDispatcher::GetForInstance(pp_instance());
     dispatcher->Send(new PpapiMsg_PPPInstance_HandleDocumentLoad(
         ppapi::API_ID_PPP_INSTANCE, pp_instance(), pending_host_id, data));
   }
 }
 
+bool PepperPluginInstanceImpl::IsPeripheralContent() const {
+  if (module_->name() != kFlashPluginName)
+    return false;
+
+  // Peripheral plugin content is defined to be peripheral when the plugin
+  // content's origin differs from the top level frame's origin. For example:
+  //  - Peripheral:      a.com -> b.com/plugin.swf
+  //  - Peripheral:      a.com -> b.com/iframe.html -> b.com/plugin.swf
+  //  - NOT peripheral:  a.com -> b.com/iframe-to-a.html -> a.com/plugin.swf
+
+  // TODO(alexmos): Update this to use the origin of the RemoteFrame when 426512
+  // is fixed. For now, case 3 in the comment above doesn't work in
+  // --site-per-process mode.
+  if (render_frame_->GetWebFrame()->top()->isWebRemoteFrame())

[raymes, 2014/10/23 21:09:03]

creis@: As an aside, we have lots of places in this file that access the main
frame through render_frame_->GetWebFrame()->view()->mainFrame(). Since all of
those are presumably going to be problematic as well, is it better just to omit
this check for now and fix them all later in one fell swoop? 

[Charlie Reis, 2014/10/23 21:51:33]

Per my announcement to chromium-dev on Tuesday, I'd like to get new code to
start working with OOPIF.  This one can be an example for updating the rest of
this file in a future CL.

[tommycli, 2014/10/23 22:21:09]

Testing this, I've discovered that cross-origin plugins don't work with OOPIF
yet. Before it can reach this point, it crashes in
https://code.google.com/p/chromium/codesearch/#chromium/src/chrome/renderer/c...

[Charlie Reis, 2014/10/23 23:50:44]

Nice find.  Can you file a bug with the Cr-Internals-Sandbox-SiteIsolation label
for that?  We'll get it triaged.

+     return true;
+
+  GURL top_frame_url = render_frame_->GetWebFrame()->top()->document().url();

[piman, 2014/10/23 21:07:34]

Can you save the result of render_frame_->GetWebFrame()->top()? It does a tree
walk, it'd be nice not to do twice.

[raymes, 2014/10/23 21:09:03]

nit: In the rest of this file we use
render_frame_->GetWebFrame()->view()->mainFrame() to get to the main frame. I
assume this is the same as the "top()" frame. Could we use it here for
consistency too? That will make it easier for someone who comes and wants to
refactor this file for site isolation (for example).

[Charlie Reis, 2014/10/23 21:51:33]

Assuming render_frame_->GetWebFrame() is a LocalFrame, that should work fine. 
(view() is null on a RemoteFrame for the time being.)

[tommycli, 2014/10/23 22:21:09]

Done.

Looks like the other places of this file use this technique:

  container()->element().document().frame()->view()->mainFrame()

If this is the same as the top() frame, that's fine also.

Do you know why you guys use the frame derived from container() instead of
render_frame_->GetWebFrame()?

[tommycli, 2014/10/23 22:21:09]

Done.

+  return plugin_url_.GetOrigin() != top_frame_url.GetOrigin();
+}
+
 void PepperPluginInstanceImpl::SetPluginThrottled(bool throttled) {
   // Do not throttle if we've already disabled power saver.
   if (!power_saver_enabled_ && throttled)
     return;
 
   plugin_throttled_ = throttled;
   SendDidChangeView();
 }
 
 }  // namespace content