[Cross-Site Isolation] Migrate entire MediaStream verticals to be per-RenderFrame.

chrome/browser/extensions/api/tab_capture/tab_capture_api.cc

Index: chrome/browser/extensions/api/tab_capture/tab_capture_api.cc
diff --git a/chrome/browser/extensions/api/tab_capture/tab_capture_api.cc b/chrome/browser/extensions/api/tab_capture/tab_capture_api.cc
index c88fbc9dc980c85266ce6da8b2dd69f04a1e8869..0a34b9a5dd82f6edf3c9808dc95be7411745220a 100644
--- a/chrome/browser/extensions/api/tab_capture/tab_capture_api.cc
+++ b/chrome/browser/extensions/api/tab_capture/tab_capture_api.cc
@@ -20,8 +20,8 @@
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
+#include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_process_host.h"
-#include "content/public/browser/render_view_host.h"
 #include "extensions/common/features/feature.h"
 #include "extensions/common/features/feature_provider.h"
 #include "extensions/common/features/simple_feature.h"
@@ -102,10 +102,6 @@ bool TabCaptureCaptureFunction::RunSync() {
     return false;
   }
 
-  content::RenderViewHost* const rvh = target_contents->GetRenderViewHost();
-  int render_process_id = rvh->GetProcess()->GetID();
-  int routing_id = rvh->GetRoutingID();
-
   // Create a constraints vector. We will modify all the constraints in this
   // vector to append our chrome specific constraints.
   std::vector<MediaStreamConstraint*> constraints;
@@ -131,8 +127,13 @@ bool TabCaptureCaptureFunction::RunSync() {
   }
 
   // Device id we use for Tab Capture.
-  std::string device_id =
-      base::StringPrintf("%i:%i", render_process_id, routing_id);
+  content::RenderFrameHost* const main_frame = target_contents->GetMainFrame();
+  // TODO(miu): We should instead use a "randomly generated device ID" scheme,
+  // like that employed by the desktop capture API.  http://crbug.com/163100
+  const std::string device_id = base::StringPrintf(
+      "web-contents-media-stream://%i:%i",

[ncarter (slow), 2014/07/10 01:17:51]

Does introducing the scheme here fix a bug? How is this different from the
scheme applied by web_contents_capture_util?

https://code.google.com/p/chromium/codesearch#chromium/src/content/browser/me...

[miu, 2014/07/10 22:16:11]

It addresses crbug.com/163100.  There isn't really a difference, except that the
code in WCCaptureUtil to "append" and "strip" the scheme was deemed unnecessary
due to the major refactoring work done in MediaStreamManager.  In short, the
device ID string can just be generated here, and then remain unmodified
throughout the media request pipeline.

Also, per the TODO comment here, I'd like to see the tab capture API employ the
secure mechanism used by the desktop capture API, where random device ID strings
are created and then later verified.  Thus, the direction I'm starting to take
here is to move device ID string generation into the chrome/ layer; and
ultimately I'd like to eliminate the parsing of the device ID string in
libcontent entirely (just like desktop capture).

[ncarter (slow), 2014/07/11 22:32:24]

Acknowledged.

+      main_frame->GetProcess()->GetID(),
+      main_frame->GetRoutingID());
 
   // Append chrome specific tab constraints.
   for (std::vector<MediaStreamConstraint*>::iterator it = constraints.begin();
@@ -144,8 +145,7 @@ bool TabCaptureCaptureFunction::RunSync() {
 
   extensions::TabCaptureRegistry* registry =
       extensions::TabCaptureRegistry::Get(GetProfile());
-  if (!registry->AddRequest(render_process_id,
-                            routing_id,
+  if (!registry->AddRequest(target_contents,
                             extension_id,
                             tab_id,
                             tab_capture::TAB_CAPTURE_STATE_NONE)) {